Package org.eclipse.collections.api

Interface RichIterable<T>

    • Method Detail

      • size

        int size()
        Returns the number of items in this iterable.
        Since:
        1.0

      • isEmpty

        boolean isEmpty()
        Returns true if this iterable has zero items.
        Since:
        1.0

      • notEmpty

        default boolean notEmpty()
        The English equivalent of !this.isEmpty()
        Since:
        1.0

      • getAny

        default T getAny()
        Returns any element of an iterable.
        Returns:
        an element of an iterable.
        Since:
        10.0

      • getFirst

        @Deprecated
T getFirst()
        Deprecated.
        in 6.0. Use OrderedIterable.getFirst() instead.
        Returns the first element of an iterable. In the case of a List it is the element at the first index. In the case of any other Collection, it is the first element that would be returned during an iteration. If the iterable is empty, null is returned. If null is a valid element of the container, then a developer would need to check to see if the iterable is empty to validate that a null result was not due to the container being empty.

        The order of Sets are not guaranteed (except for TreeSets and other Ordered Set implementations), so if you use this method, the first element could be any element from the Set.

        Since:
        1.0

      • getLast

        @Deprecated
T getLast()
        Deprecated.
        in 6.0. Use OrderedIterable.getLast() instead.
        Returns the last element of an iterable. In the case of a List it is the element at the last index. In the case of any other Collection, it is the last element that would be returned during an iteration. If the iterable is empty, null is returned. If null is a valid element of the container, then a developer would need to check to see if the iterable is empty to validate that a null result was not due to the container being empty.

        The order of Sets are not guaranteed (except for TreeSets and other Ordered Set implementations), so if you use this method, the last element could be any element from the Set.

        Since:
        1.0

      • getOnly

        default T getOnly()
        Returns the element if the iterable has exactly one element. Otherwise, throw IllegalStateException.
        Returns:
        an element of an iterable.
        Throws:
        IllegalStateException - if iterable is empty or has multiple elements.
        Since:
        8.0

      • contains

        boolean contains​(Object object)
        Returns true if the iterable has an element which responds true to element.equals(object).
        Since:
        1.0

      • containsBy

        default <V> boolean containsBy​(Function<? super T,​? extends V> function,
                               V value)
        Returns true if the iterable has an element which responds true to element.equals(value) after applying the specified function to the element.
        Since:
        10.3

      • containsAny

        default boolean containsAny​(Collection<?> source)
        Returns true if any of the elements in source is contained in this collection.
        Since:
        11.1

      • containsNone

        default boolean containsNone​(Collection<?> source)
        Returns true if none of the elements in source are contained in this collection.
        Since:
        11.1

      • containsAnyIterable

        default boolean containsAnyIterable​(Iterable<?> source)
        Returns true if any of the elements in source is contained in this collection.
        Since:
        11.1

      • containsNoneIterable

        default boolean containsNoneIterable​(Iterable<?> source)
        Returns true if none of the elements in source are contained in this collection.
        Since:
        11.1

      • containsAllIterable

        boolean containsAllIterable​(Iterable<?> source)
        Returns true if all elements in source are contained in this collection.
        Since:
        1.0

      • containsAllArguments

        boolean containsAllArguments​(Object... elements)
        Returns true if all elements in the specified var arg array are contained in this collection.
        Since:
        1.0

      • tap

        RichIterable<T> tap​(Procedure<? super T> procedure)
        Executes the Procedure for each element in the iterable and returns this.

        Example using a Java 8 lambda expression: 

         RichIterable<Person> tapped =
     people.tap(person -> LOGGER.info(person.getName()));
        Since:
        6.0
        See Also:
        each(Procedure), forEach(Procedure)

      • select

        RichIterable<T> select​(Predicate<? super T> predicate)
        Returns all elements of the source collection that return true when evaluating the predicate. This method is also commonly called filter.

        Example using a Java 8 lambda expression: 

         RichIterable<Person> selected =
     people.select(person -> person.getAddress().getCity().equals("London"));
        Since:
        1.0

      • select

        <R extends Collection<T>> R select​(Predicate<? super T> predicate,
                                   R target)
        Same as the select method with one parameter but uses the specified target collection for the results.

        Example using a Java 8 lambda expression: 

         MutableList<Person> selected =
     people.select(person -> person.person.getLastName().equals("Smith"), Lists.mutable.empty());

        Parameters:
        predicate - a Predicate to use as the select criteria
        target - the Collection to append to for all elements in this RichIterable that meet select criteria predicate
        Returns:
        target, which contains appended elements as a result of the select criteria
        Since:
        1.0
        See Also:
        select(Predicate)

      • selectWith

        <P> RichIterable<T> selectWith​(Predicate2<? super T,​? super P> predicate,
                               P parameter)
        Similar to select(Predicate), except with an evaluation parameter for the second generic argument in Predicate2.

        E.g. return a Collection of Person elements where the person has an age greater than or equal to 18 years

        Example using a Java 8 lambda expression: 

         RichIterable<Person> selected =
     people.selectWith((Person person, Integer age) -> person.getAge()>= age, Integer.valueOf(18));
        Parameters:
        predicate - a Predicate2 to use as the select criteria
        parameter - a parameter to pass in for evaluation of the second argument P in predicate
        Since:
        5.0
        See Also:
        select(Predicate)

      • selectWith

        <P,​R extends Collection<T>> R selectWith​(Predicate2<? super T,​? super P> predicate,
                                               P parameter,
                                               R targetCollection)
        Similar to select(Predicate, Collection), except with an evaluation parameter for the second generic argument in Predicate2.

        E.g. return a Collection of Person elements where the person has an age greater than or equal to 18 years

        Example using a Java 8 lambda expression: 

         MutableList<Person> selected =
     people.selectWith((Person person, Integer age) -> person.getAge()>= age, Integer.valueOf(18), Lists.mutable.empty());
        Parameters:
        predicate - a Predicate2 to use as the select criteria
        parameter - a parameter to pass in for evaluation of the second argument P in predicate
        targetCollection - the Collection to append to for all elements in this RichIterable that meet select criteria predicate
        Returns:
        targetCollection, which contains appended elements as a result of the select criteria
        Since:
        1.0
        See Also:
        select(Predicate), select(Predicate, Collection)

      • reject

        RichIterable<T> reject​(Predicate<? super T> predicate)
        Returns all elements of the source collection that return false when evaluating of the predicate. This method is also sometimes called filterNot and is the equivalent of calling iterable.select(Predicates.not(predicate)).

        Example using a Java 8 lambda expression: 

         RichIterable<Person> rejected =
     people.reject(person -> person.person.getLastName().equals("Smith"));
        Parameters:
        predicate - a Predicate to use as the reject criteria
        Returns:
        a RichIterable that contains elements that cause Predicate.accept(Object) method to evaluate to false
        Since:
        1.0

      • rejectWith

        <P> RichIterable<T> rejectWith​(Predicate2<? super T,​? super P> predicate,
                               P parameter)
        Similar to reject(Predicate), except with an evaluation parameter for the second generic argument in Predicate2.

        E.g. return a Collection of Person elements where the person has an age greater than or equal to 18 years

        Example using a Java 8 lambda expression: 

         RichIterable<Person> rejected =
     people.rejectWith((Person person, Integer age) -> person.getAge() < age, Integer.valueOf(18));
        Parameters:
        predicate - a Predicate2 to use as the select criteria
        parameter - a parameter to pass in for evaluation of the second argument P in predicate
        Since:
        5.0
        See Also:
        select(Predicate)

      • reject

        <R extends Collection<T>> R reject​(Predicate<? super T> predicate,
                                   R target)
        Same as the reject method with one parameter but uses the specified target collection for the results.

        Example using a Java 8 lambda expression: 

         MutableList<Person> rejected =
     people.reject(person -> person.person.getLastName().equals("Smith"), Lists.mutable.empty());
        Parameters:
        predicate - a Predicate to use as the reject criteria
        target - the Collection to append to for all elements in this RichIterable that cause Predicate#accept(Object) method to evaluate to false
        Returns:
        target, which contains appended elements as a result of the reject criteria
        Since:
        1.0

      • rejectWith

        <P,​R extends Collection<T>> R rejectWith​(Predicate2<? super T,​? super P> predicate,
                                               P parameter,
                                               R targetCollection)
        Similar to reject(Predicate, Collection), except with an evaluation parameter for the second generic argument in Predicate2.

        E.g. return a Collection of Person elements where the person has an age greater than or equal to 18 years

        Example using a Java 8 lambda expression: 

         MutableList<Person> rejected =
     people.rejectWith((Person person, Integer age) -> person.getAge() < age, Integer.valueOf(18), Lists.mutable.empty());
        Parameters:
        predicate - a Predicate2 to use as the reject criteria
        parameter - a parameter to pass in for evaluation of the second argument P in predicate
        targetCollection - the Collection to append to for all elements in this RichIterable that cause Predicate#accept(Object) method to evaluate to false
        Returns:
        targetCollection, which contains appended elements as a result of the reject criteria
        Since:
        1.0
        See Also:
        reject(Predicate), reject(Predicate, Collection)

      • partition

        PartitionIterable<T> partition​(Predicate<? super T> predicate)
        Filters a collection into a PartitionedIterable based on the evaluation of the predicate.

        Example using a Java 8 lambda expression: 

         PartitionIterable<Person> newYorkersAndNonNewYorkers =
     people.partition(person -> person.getAddress().getState().getName().equals("New York"));
        Since:
        1.0.

      • partitionWith

        <P> PartitionIterable<T> partitionWith​(Predicate2<? super T,​? super P> predicate,
                                       P parameter)
        Filters a collection into a PartitionIterable based on the evaluation of the predicate.

        Example using a Java 8 lambda expression: 

         PartitionIterable<Person> newYorkersAndNonNewYorkers =
     people.partitionWith((Person person, String state) -> person.getAddress().getState().getName().equals(state), "New York");
        Since:
        5.0.

      • selectInstancesOf

        <S> RichIterable<S> selectInstancesOf​(Class<S> clazz)
        Returns all elements of the source collection that are instances of the Class clazz. 
         RichIterable<Integer> integers =
     List.mutable.with(new Integer(0), new Long(0L), new Double(0.0)).selectInstancesOf(Integer.class);
        Since:
        2.0

      • collect

        <V> RichIterable<V> collect​(Function<? super T,​? extends V> function)
        Returns a new collection with the results of applying the specified function on each element of the source collection. This method is also commonly called transform or map.

        Example using a Java 8 lambda expression: 

         RichIterable<String> names =
     people.collect(person -> person.getFirstName() + " " + person.getLastName());
        Since:
        1.0

      • collect

        <V,​R extends Collection<V>> R collect​(Function<? super T,​? extends V> function,
                                            R target)
        Same as collect(Function), except that the results are gathered into the specified target collection.

        Example using a Java 8 lambda expression: 

         MutableList<String> names =
     people.collect(person -> person.getFirstName() + " " + person.getLastName(), Lists.mutable.empty());
        Parameters:
        function - a Function to use as the collect transformation function
        target - the Collection to append to for all elements in this RichIterable that meet select criteria function
        Returns:
        target, which contains appended elements as a result of the collect transformation
        Since:
        1.0
        See Also:
        collect(Function)

      • collectBoolean

        BooleanIterable collectBoolean​(BooleanFunction<? super T> booleanFunction)
        Returns a new primitive boolean iterable with the results of applying the specified function on each element of the source collection. This method is also commonly called transform or map.

        Example using a Java 8 lambda expression: 

         BooleanIterable licenses =
     people.collectBoolean(person -> person.hasDrivingLicense());
        Since:
        4.0

      • collectBoolean

        default <R extends MutableBooleanCollection> R collectBoolean​(BooleanFunction<? super T> booleanFunction,
                                                              R target)
        Same as collectBoolean(BooleanFunction), except that the results are gathered into the specified target collection.

        Example using a Java 8 lambda expression: 

         BooleanArrayList licenses =
     people.collectBoolean(person -> person.hasDrivingLicense(), new BooleanArrayList());
        Parameters:
        booleanFunction - a BooleanFunction to use as the collect transformation function
        target - the MutableBooleanCollection to append to for all elements in this RichIterable
        Returns:
        target, which contains appended elements as a result of the collect transformation
        Since:
        5.0

      • collectByte

        ByteIterable collectByte​(ByteFunction<? super T> byteFunction)
        Returns a new primitive byte iterable with the results of applying the specified function on each element of the source collection. This method is also commonly called transform or map.

        Example using a Java 8 lambda expression: 

         ByteIterable bytes =
     people.collectByte(person -> person.getCode());
        Since:
        4.0

      • collectByte

        default <R extends MutableByteCollection> R collectByte​(ByteFunction<? super T> byteFunction,
                                                        R target)
        Same as collectByte(ByteFunction), except that the results are gathered into the specified target collection.

        Example using a Java 8 lambda expression: 

         ByteArrayList bytes =
     people.collectByte(person -> person.getCode(), new ByteArrayList());
        Parameters:
        byteFunction - a ByteFunction to use as the collect transformation function
        target - the MutableByteCollection to append to for all elements in this RichIterable
        Returns:
        target, which contains appended elements as a result of the collect transformation
        Since:
        5.0

      • collectChar

        CharIterable collectChar​(CharFunction<? super T> charFunction)
        Returns a new primitive char iterable with the results of applying the specified function on each element of the source collection. This method is also commonly called transform or map.

        Example using a Java 8 lambda expression: 

         CharIterable chars =
     people.collectChar(person -> person.getMiddleInitial());
        Since:
        4.0

      • collectChar

        default <R extends MutableCharCollection> R collectChar​(CharFunction<? super T> charFunction,
                                                        R target)
        Same as collectChar(CharFunction), except that the results are gathered into the specified target collection.

        Example using a Java 8 lambda expression: 

         CharArrayList chars =
     people.collectChar(person -> person.getMiddleInitial(), new CharArrayList());
        Parameters:
        charFunction - a CharFunction to use as the collect transformation function
        target - the MutableCharCollection to append to for all elements in this RichIterable
        Returns:
        target, which contains appended elements as a result of the collect transformation
        Since:
        5.0

      • collectDouble

        DoubleIterable collectDouble​(DoubleFunction<? super T> doubleFunction)
        Returns a new primitive double iterable with the results of applying the specified function on each element of the source collection. This method is also commonly called transform or map.

        Example using a Java 8 lambda expression: 

         DoubleIterable doubles =
     people.collectDouble(person -> person.getMilesFromNorthPole());
        Since:
        4.0

      • collectDouble

        default <R extends MutableDoubleCollection> R collectDouble​(DoubleFunction<? super T> doubleFunction,
                                                            R target)
        Same as collectDouble(DoubleFunction), except that the results are gathered into the specified target collection.

        Example using a Java 8 lambda expression: 

         DoubleArrayList doubles =
     people.collectDouble(person -> person.getMilesFromNorthPole(), new DoubleArrayList());
        Parameters:
        doubleFunction - a DoubleFunction to use as the collect transformation function
        target - the MutableDoubleCollection to append to for all elements in this RichIterable
        Returns:
        target, which contains appended elements as a result of the collect transformation
        Since:
        5.0

      • collectFloat

        FloatIterable collectFloat​(FloatFunction<? super T> floatFunction)
        Returns a new primitive float iterable with the results of applying the specified function on each element of the source collection. This method is also commonly called transform or map.

        Example using a Java 8 lambda expression: 

         FloatIterable floats =
     people.collectFloat(person -> person.getHeightInInches());
        Since:
        4.0

      • collectFloat

        default <R extends MutableFloatCollection> R collectFloat​(FloatFunction<? super T> floatFunction,
                                                          R target)
        Same as collectFloat(FloatFunction), except that the results are gathered into the specified target collection.

        Example using a Java 8 lambda expression: 

         FloatArrayList floats =
     people.collectFloat(person -> person.getHeightInInches(), new FloatArrayList());
        Parameters:
        floatFunction - a FloatFunction to use as the collect transformation function
        target - the MutableFloatCollection to append to for all elements in this RichIterable
        Returns:
        target, which contains appended elements as a result of the collect transformation
        Since:
        5.0

      • collectInt

        IntIterable collectInt​(IntFunction<? super T> intFunction)
        Returns a new primitive int iterable with the results of applying the specified function on each element of the source collection. This method is also commonly called transform or map.

        Example using a Java 8 lambda expression: 

         IntIterable ints =
     people.collectInt(person -> person.getAge());
        Since:
        4.0

      • collectInt

        default <R extends MutableIntCollection> R collectInt​(IntFunction<? super T> intFunction,
                                                      R target)
        Same as collectInt(IntFunction), except that the results are gathered into the specified target collection.

        Example using a Java 8 lambda expression: 

         IntArrayList ints =
     people.collectInt(person -> person.getAge(), new IntArrayList());
        Parameters:
        intFunction - a IntFunction to use as the collect transformation function
        target - the MutableIntCollection to append to for all elements in this RichIterable
        Returns:
        target, which contains appended elements as a result of the collect transformation
        Since:
        5.0

      • collectLong

        LongIterable collectLong​(LongFunction<? super T> longFunction)
        Returns a new primitive long iterable with the results of applying the specified function on each element of the source collection. This method is also commonly called transform or map.

        Example using a Java 8 lambda expression: 

         LongIterable longs =
     people.collectLong(person -> person.getGuid());
        Since:
        4.0

      • collectLong

        default <R extends MutableLongCollection> R collectLong​(LongFunction<? super T> longFunction,
                                                        R target)
        Same as collectLong(LongFunction), except that the results are gathered into the specified target collection.

        Example using a Java 8 lambda expression: 

         LongArrayList longs =
     people.collectLong(person -> person.getGuid(), new LongArrayList());
        Parameters:
        longFunction - a LongFunction to use as the collect transformation function
        target - the MutableLongCollection to append to for all elements in this RichIterable
        Returns:
        target, which contains appended elements as a result of the collect transformation
        Since:
        5.0

      • collectShort

        ShortIterable collectShort​(ShortFunction<? super T> shortFunction)
        Returns a new primitive short iterable with the results of applying the specified function on each element of the source collection. This method is also commonly called transform or map.

        Example using a Java 8 lambda expression: 

         ShortIterable shorts =
     people.collectShort(person -> person.getNumberOfJunkMailItemsReceivedPerMonth());
        Since:
        4.0

      • collectShort

        default <R extends MutableShortCollection> R collectShort​(ShortFunction<? super T> shortFunction,
                                                          R target)
        Same as collectShort(ShortFunction), except that the results are gathered into the specified target collection.

        Example using a Java 8 lambda expression: 

         ShortArrayList shorts =
     people.collectShort(person -> person.getNumberOfJunkMailItemsReceivedPerMonth, new ShortArrayList());
        Parameters:
        shortFunction - a ShortFunction to use as the collect transformation function
        target - the MutableShortCollection to append to for all elements in this RichIterable
        Returns:
        target, which contains appended elements as a result of the collect transformation
        Since:
        5.0

      • collectWith

        <P,​V> RichIterable<V> collectWith​(Function2<? super T,​? super P,​? extends V> function,
                                        P parameter)
        Same as collect(Function) with a Function2 and specified parameter which is passed to the block.

        Example using a Java 8 lambda expression: 

         RichIterable<Integer> integers =
     Lists.mutable.with(1, 2, 3).collectWith((each, parameter) -> each + parameter, Integer.valueOf(1));
        Parameters:
        function - A Function2 to use as the collect transformation function
        parameter - A parameter to pass in for evaluation of the second argument P in function
        Returns:
        A new RichIterable that contains the transformed elements returned by Function2.value(Object, Object)
        Since:
        5.0
        See Also:
        collect(Function)

      • collectWith

        <P,​V,​R extends Collection<V>> R collectWith​(Function2<? super T,​? super P,​? extends V> function,
                                                        P parameter,
                                                        R targetCollection)
        Same as collectWith but with a targetCollection parameter to gather the results.

        Example using a Java 8 lambda expression: 

         MutableSet<Integer> integers =
     Lists.mutable.with(1, 2, 3).collectWith((each, parameter) -> each + parameter, Integer.valueOf(1), Sets.mutable.empty());
        Parameters:
        function - a Function2 to use as the collect transformation function
        parameter - a parameter to pass in for evaluation of the second argument P in function
        targetCollection - the Collection to append to for all elements in this RichIterable that meet select criteria function
        Returns:
        targetCollection, which contains appended elements as a result of the collect transformation
        Since:
        1.0

      • collectIf

        <V> RichIterable<V> collectIf​(Predicate<? super T> predicate,
                              Function<? super T,​? extends V> function)
        Returns a new collection with the results of applying the specified function on each element of the source collection, but only for those elements which return true upon evaluation of the predicate. This is the optimized equivalent of calling iterable.select(predicate).collect(function).

        Example using a Java 8 lambda and method reference: 

         RichIterable<String> strings = Lists.mutable.with(1, 2, 3).collectIf(e -> e != null, Object::toString);

        Example using Predicates factory: 

         RichIterable<String> strings = Lists.mutable.with(1, 2, 3).collectIf(Predicates.notNull(), Functions.getToString());
        Since:
        1.0

      • collectIf

        <V,​R extends Collection<V>> R collectIf​(Predicate<? super T> predicate,
                                              Function<? super T,​? extends V> function,
                                              R target)
        Same as the collectIf method with two parameters but uses the specified target collection for the results.
        Parameters:
        predicate - a Predicate to use as the select criteria
        function - a Function to use as the collect transformation function
        target - the Collection to append to for all elements in this RichIterable that meet the collect criteria predicate
        Returns:
        targetCollection, which contains appended elements as a result of the collect criteria and transformation
        Since:
        1.0
        See Also:
        collectIf(Predicate, Function)

      • flatCollect

        <V> RichIterable<V> flatCollect​(Function<? super T,​? extends Iterable<V>> function)
        flatCollect is a special case of collect(Function). With collect, when the Function returns a collection, the result is a collection of collections. flatCollect outputs a single "flattened" collection instead. This method is commonly called flatMap.

        Consider the following example where we have a Person class, and each Person has a list of Address objects. Take the following Function: 

         Function<Person, List<Address>> addressFunction = Person::getAddresses;
 RichIterable<Person> people = ...;
        Using collect returns a collection of collections of addresses. 
         RichIterable<List<Address>> addresses = people.collect(addressFunction);
        Using flatCollect returns a single flattened list of addresses. 
         RichIterable<Address> addresses = people.flatCollect(addressFunction);
        Parameters:
        function - The Function to apply
        Returns:
        a new flattened collection produced by applying the given function
        Since:
        1.0

      • flatCollectByte

        default <R extends MutableByteCollection> R flatCollectByte​(Function<? super T,​? extends ByteIterable> function,
                                                            R target)
        Same as flatCollect, only the results are collected into the target collection.
        Parameters:
        function - The Function to apply
        target - The collection into which results should be added.
        Returns:
        target, which will contain a flattened collection of results produced by applying the given function
        See Also:
        flatCollect(Function)

      • flatCollectChar

        default <R extends MutableCharCollection> R flatCollectChar​(Function<? super T,​? extends CharIterable> function,
                                                            R target)
        Same as flatCollect, only the results are collected into the target collection.
        Parameters:
        function - The Function to apply
        target - The collection into which results should be added.
        Returns:
        target, which will contain a flattened collection of results produced by applying the given function
        See Also:
        flatCollect(Function)

      • flatCollectInt

        default <R extends MutableIntCollection> R flatCollectInt​(Function<? super T,​? extends IntIterable> function,
                                                          R target)
        Same as flatCollect, only the results are collected into the target collection.
        Parameters:
        function - The Function to apply
        target - The collection into which results should be added.
        Returns:
        target, which will contain a flattened collection of results produced by applying the given function
        See Also:
        flatCollect(Function)

      • flatCollectShort

        default <R extends MutableShortCollection> R flatCollectShort​(Function<? super T,​? extends ShortIterable> function,
                                                              R target)
        Same as flatCollect, only the results are collected into the target collection.
        Parameters:
        function - The Function to apply
        target - The collection into which results should be added.
        Returns:
        target, which will contain a flattened collection of results produced by applying the given function
        See Also:
        flatCollect(Function)

      • flatCollectDouble

        default <R extends MutableDoubleCollection> R flatCollectDouble​(Function<? super T,​? extends DoubleIterable> function,
                                                                R target)
        Same as flatCollect, only the results are collected into the target collection.
        Parameters:
        function - The Function to apply
        target - The collection into which results should be added.
        Returns:
        target, which will contain a flattened collection of results produced by applying the given function
        See Also:
        flatCollect(Function)

      • flatCollectFloat

        default <R extends MutableFloatCollection> R flatCollectFloat​(Function<? super T,​? extends FloatIterable> function,
                                                              R target)
        Same as flatCollect, only the results are collected into the target collection.
        Parameters:
        function - The Function to apply
        target - The collection into which results should be added.
        Returns:
        target, which will contain a flattened collection of results produced by applying the given function
        See Also:
        flatCollect(Function)

      • flatCollectLong

        default <R extends MutableLongCollection> R flatCollectLong​(Function<? super T,​? extends LongIterable> function,
                                                            R target)
        Same as flatCollect, only the results are collected into the target collection.
        Parameters:
        function - The Function to apply
        target - The collection into which results should be added.
        Returns:
        target, which will contain a flattened collection of results produced by applying the given function
        See Also:
        flatCollect(Function)

      • flatCollectBoolean

        default <R extends MutableBooleanCollection> R flatCollectBoolean​(Function<? super T,​? extends BooleanIterable> function,
                                                                  R target)
        Same as flatCollect, only the results are collected into the target collection.
        Parameters:
        function - The Function to apply
        target - The collection into which results should be added.
        Returns:
        target, which will contain a flattened collection of results produced by applying the given function
        See Also:
        flatCollect(Function)

      • flatCollectWith

        default <P,​V> RichIterable<V> flatCollectWith​(Function2<? super T,​? super P,​? extends Iterable<V>> function,
                                                    P parameter)
        Since:
        9.2

      • flatCollect

        <V,​R extends Collection<V>> R flatCollect​(Function<? super T,​? extends Iterable<V>> function,
                                                R target)
        Same as flatCollect, only the results are collected into the target collection.
        Parameters:
        function - The Function to apply
        target - The collection into which results should be added.
        Returns:
        target, which will contain a flattened collection of results produced by applying the given function
        See Also:
        flatCollect(Function)

      • flatCollectWith

        default <P,​V,​R extends Collection<V>> R flatCollectWith​(Function2<? super T,​? super P,​? extends Iterable<V>> function,
                                                                    P parameter,
                                                                    R target)
        Since:
        9.2

      • detect

        T detect​(Predicate<? super T> predicate)
        Returns the first element of the iterable for which the predicate evaluates to true or null in the case where no element returns true. This method is commonly called find.

        Example using a Java 8 lambda expression: 

         Person person =
     people.detect(person -> person.getFirstName().equals("John") && person.getLastName().equals("Smith"));
        Since:
        1.0

      • detectWith

        <P> T detectWith​(Predicate2<? super T,​? super P> predicate,
                 P parameter)
        Returns the first element that evaluates to true for the specified predicate2 and parameter, or null if none evaluate to true.

        Example using a Java 8 lambda expression: 

         Person person =
     people.detectWith((person, fullName) -> person.getFullName().equals(fullName), "John Smith");
        Since:
        5.0

      • detectOptional

        Optional<T> detectOptional​(Predicate<? super T> predicate)
        Returns the first element of the iterable for which the predicate evaluates to true as an Optional. This method is commonly called find.

        Example using a Java 8 lambda expression: 

         Person person =
     people.detectOptional(person -> person.getFirstName().equals("John") && person.getLastName().equals("Smith"));

        Throws:
        NullPointerException - if the element selected is null
        Since:
        8.0

      • detectWithOptional

        <P> Optional<T> detectWithOptional​(Predicate2<? super T,​? super P> predicate,
                                   P parameter)
        Returns the first element that evaluates to true for the specified predicate2 and parameter as an Optional.

        Example using a Java 8 lambda expression: 

         Optional<Person> person =
     people.detectWithOptional((person, fullName) -> person.getFullName().equals(fullName), "John Smith");

        Throws:
        NullPointerException - if the element selected is null
        Since:
        8.0

      • detectIfNone

        default T detectIfNone​(Predicate<? super T> predicate,
                       Function0<? extends T> function)
        Returns the first element of the iterable for which the predicate evaluates to true. If no element matches the predicate, then returns the value of applying the specified function.
        Since:
        1.0

      • detectWithIfNone

        <P> T detectWithIfNone​(Predicate2<? super T,​? super P> predicate,
                       P parameter,
                       Function0<? extends T> function)
        Returns the first element of the iterable that evaluates to true for the specified predicate2 and parameter, or returns the value of evaluating the specified function.
        Since:
        5.0

      • count

        int count​(Predicate<? super T> predicate)
        Return the total number of elements that answer true to the specified predicate.

        Example using a Java 8 lambda expression: 

         int count =
     people.count(person -> person.getAddress().getState().getName().equals("New York"));
        Since:
        1.0

      • countWith

        <P> int countWith​(Predicate2<? super T,​? super P> predicate,
                  P parameter)
        Returns the total number of elements that evaluate to true for the specified predicate. 
        e.g.
 return lastNames.countWith(Predicates2.equal(), "Smith");

      • anySatisfy

        boolean anySatisfy​(Predicate<? super T> predicate)
        Returns true if the predicate evaluates to true for any element of the iterable. Returns false if the iterable is empty, or if no element returned true when evaluating the predicate.
        Since:
        1.0

      • anySatisfyWith

        <P> boolean anySatisfyWith​(Predicate2<? super T,​? super P> predicate,
                           P parameter)
        Returns true if the predicate evaluates to true for any element of the collection, or return false. Returns false if the collection is empty.
        Since:
        5.0

      • allSatisfy

        boolean allSatisfy​(Predicate<? super T> predicate)
        Returns true if the predicate evaluates to true for every element of the iterable or if the iterable is empty. Otherwise, returns false.
        Since:
        1.0

      • allSatisfyWith

        <P> boolean allSatisfyWith​(Predicate2<? super T,​? super P> predicate,
                           P parameter)
        Returns true if the predicate evaluates to true for every element of the collection, or returns false.
        Since:
        5.0

      • noneSatisfy

        boolean noneSatisfy​(Predicate<? super T> predicate)
        Returns true if the predicate evaluates to false for every element of the iterable or if the iterable is empty. Otherwise, returns false.
        Since:
        3.0

      • noneSatisfyWith

        <P> boolean noneSatisfyWith​(Predicate2<? super T,​? super P> predicate,
                            P parameter)
        Returns true if the predicate evaluates to false for every element of the collection, or return false. Returns true if the collection is empty.
        Since:
        5.0

      • injectInto

        <IV> IV injectInto​(IV injectedValue,
                   Function2<? super IV,​? super T,​? extends IV> function)
        Returns the final result of evaluating function using each element of the iterable and the previous evaluation result as the parameters. The injected value is used for the first parameter of the first evaluation, and the current item in the iterable is used as the second parameter. This method is commonly called fold or sometimes reduce.
        Since:
        1.0

      • injectInto

        @Deprecated
int injectInto​(int injectedValue,
               IntObjectToIntFunction<? super T> function)
        Deprecated.
        since 11.1 - use injectIntoInt instead
        Returns the final int result of evaluating function using each element of the iterable and the previous evaluation result as the parameters. The injected value is used for the first parameter of the first evaluation, and the current item in the iterable is used as the second parameter.
        Since:
        1.0

      • injectIntoInt

        default int injectIntoInt​(int injectedValue,
                          IntObjectToIntFunction<? super T> function)
        Returns the final int result of evaluating function using each element of the iterable and the previous evaluation result as the parameters. The injected value is used for the first parameter of the first evaluation, and the current item in the iterable is used as the second parameter.
        Since:
        11.1

      • injectInto

        @Deprecated
long injectInto​(long injectedValue,
                LongObjectToLongFunction<? super T> function)
        Deprecated.
        since 11.1 - use injectIntoLong instead
        Returns the final long result of evaluating function using each element of the iterable and the previous evaluation result as the parameters. The injected value is used for the first parameter of the first evaluation, and the current item in the iterable is used as the second parameter.
        Since:
        1.0

      • injectIntoLong

        default long injectIntoLong​(long injectedValue,
                            LongObjectToLongFunction<? super T> function)
        Returns the final long result of evaluating function using each element of the iterable and the previous evaluation result as the parameters. The injected value is used for the first parameter of the first evaluation, and the current item in the iterable is used as the second parameter.
        Since:
        11.1

      • injectInto

        @Deprecated
float injectInto​(float injectedValue,
                 FloatObjectToFloatFunction<? super T> function)
        Deprecated.
        since 11.1 - use injectIntoFloat instead
        Returns the final float result of evaluating function using each element of the iterable and the previous evaluation result as the parameters. The injected value is used for the first parameter of the first evaluation, and the current item in the iterable is used as the second parameter.
        Since:
        2.0

      • injectIntoFloat

        default float injectIntoFloat​(float injectedValue,
                              FloatObjectToFloatFunction<? super T> function)
        Returns the final float result of evaluating function using each element of the iterable and the previous evaluation result as the parameters. The injected value is used for the first parameter of the first evaluation, and the current item in the iterable is used as the second parameter.
        Since:
        11.1

      • injectInto

        @Deprecated
double injectInto​(double injectedValue,
                  DoubleObjectToDoubleFunction<? super T> function)
        Deprecated.
        since 11.1 - use injectIntoDouble instead
        Returns the final double result of evaluating function using each element of the iterable and the previous evaluation result as the parameters. The injected value is used for the first parameter of the first evaluation, and the current item in the iterable is used as the second parameter.
        Since:
        1.0

      • injectIntoDouble

        default double injectIntoDouble​(double injectedValue,
                                DoubleObjectToDoubleFunction<? super T> function)
        Returns the final double result of evaluating function using each element of the iterable and the previous evaluation result as the parameters. The injected value is used for the first parameter of the first evaluation, and the current item in the iterable is used as the second parameter.
        Since:
        11.1

      • into

        <R extends Collection<T>> R into​(R target)
        Adds all the elements in this iterable to the specific target Collection.
        Since:
        8.0

      • toList

        MutableList<T> toList()
        Converts the collection to a MutableList implementation.
        Since:
        1.0

      • toSortedList

        default MutableList<T> toSortedList()
        Converts the collection to a MutableList implementation and sorts it using the natural order of the elements.
        Since:
        1.0

      • toSortedList

        default MutableList<T> toSortedList​(Comparator<? super T> comparator)
        Converts the collection to a MutableList implementation and sorts it using the specified comparator.
        Since:
        1.0

      • toSortedListBy

        default <V extends Comparable<? super V>> MutableList<T> toSortedListBy​(Function<? super T,​? extends V> function)
        Converts the collection to a MutableList implementation and sorts it based on the natural order of the attribute returned by function.
        Since:
        1.0

      • toSet

        MutableSet<T> toSet()
        Converts the collection to a MutableSet implementation.
        Since:
        1.0

      • toSortedSet

        MutableSortedSet<T> toSortedSet()
        Converts the collection to a MutableSortedSet implementation and sorts it using the natural order of the elements.
        Since:
        1.0

      • toSortedSet

        MutableSortedSet<T> toSortedSet​(Comparator<? super T> comparator)
        Converts the collection to a MutableSortedSet implementation and sorts it using the specified comparator.
        Since:
        1.0

      • toSortedSetBy

        default <V extends Comparable<? super V>> MutableSortedSet<T> toSortedSetBy​(Function<? super T,​? extends V> function)
        Converts the collection to a MutableSortedSet implementation and sorts it based on the natural order of the attribute returned by function.
        Since:
        1.0

      • toBag

        MutableBag<T> toBag()
        Converts the collection to the default MutableBag implementation.
        Since:
        1.0

      • toSortedBag

        MutableSortedBag<T> toSortedBag()
        Converts the collection to a MutableSortedBag implementation and sorts it using the natural order of the elements.
        Since:
        6.0

      • toSortedBag

        MutableSortedBag<T> toSortedBag​(Comparator<? super T> comparator)
        Converts the collection to the MutableSortedBag implementation and sorts it using the specified comparator.
        Since:
        6.0

      • toSortedBagBy

        default <V extends Comparable<? super V>> MutableSortedBag<T> toSortedBagBy​(Function<? super T,​? extends V> function)
        Converts the collection to a MutableSortedBag implementation and sorts it based on the natural order of the attribute returned by function.
        Since:
        6.0

      • toMap

        <NK,​NV> MutableMap<NK,​NV> toMap​(Function<? super T,​? extends NK> keyFunction,
                                            Function<? super T,​? extends NV> valueFunction)
        Converts the collection to a MutableMap implementation using the specified key and value functions.
        Since:
        1.0

      • toMap

        default <NK,​NV,​R extends Map<NK,​NV>> R toMap​(Function<? super T,​? extends NK> keyFunction,
                                                               Function<? super T,​? extends NV> valueFunction,
                                                               R target)
        Same as toMap(Function, Function), except that the results are gathered into the specified target map.
        Since:
        10.0

      • toSortedMap

        <NK,​NV> MutableSortedMap<NK,​NV> toSortedMap​(Function<? super T,​? extends NK> keyFunction,
                                                        Function<? super T,​? extends NV> valueFunction)
        Converts the collection to a MutableSortedMap implementation using the specified key and value functions sorted by the key elements' natural ordering.
        Since:
        1.0

      • toSortedMap

        <NK,​NV> MutableSortedMap<NK,​NV> toSortedMap​(Comparator<? super NK> comparator,
                                                        Function<? super T,​? extends NK> keyFunction,
                                                        Function<? super T,​? extends NV> valueFunction)
        Converts the collection to a MutableSortedMap implementation using the specified key and value functions sorted by the given comparator.
        Since:
        1.0

      • toSortedMapBy

        default <KK extends Comparable<? super KK>,​NK,​NV> MutableSortedMap<NK,​NV> toSortedMapBy​(Function<? super NK,​KK> sortBy,
                                                                                                          Function<? super T,​? extends NK> keyFunction,
                                                                                                          Function<? super T,​? extends NV> valueFunction)
        Converts the collection to a MutableSortedMap implementation using the specified key and value functions and sorts it based on the natural order of the attribute returned by sortBy function.

      • toBiMap

        <NK,​NV> MutableBiMap<NK,​NV> toBiMap​(Function<? super T,​? extends NK> keyFunction,
                                                Function<? super T,​? extends NV> valueFunction)
        Converts the collection to a BiMap implementation using the specified key and value functions.
        Since:
        10.0

      • toImmutableList

        default ImmutableList<T> toImmutableList()
        Converts the RichIterable to the default ImmutableList implementation.
        Since:
        11.0

      • toImmutableSet

        default ImmutableSet<T> toImmutableSet()
        Converts the RichIterable to the default ImmutableSet implementation.
        Since:
        11.0

      • toImmutableBag

        default ImmutableBag<T> toImmutableBag()
        Converts the RichIterable to the default ImmutableBag implementation.
        Since:
        11.0

      • toImmutableSortedList

        default ImmutableList<T> toImmutableSortedList()
        Converts the RichIterable to the default sorted ImmutableList implementation.
        Since:
        11.0

      • toImmutableSortedList

        default ImmutableList<T> toImmutableSortedList​(Comparator<? super T> comparator)
        Converts the collection to an ImmutableList implementation and sorts it using the specified comparator.
        Since:
        11.0

      • toImmutableSortedListBy

        default <V extends Comparable<? super V>> ImmutableList<T> toImmutableSortedListBy​(Function<? super T,​? extends V> function)
        Converts the collection to an ImmutableList implementation and sorts it based on the natural order of the attribute returned by function.
        Since:
        11.0

      • toImmutableSortedSet

        default ImmutableSortedSet<T> toImmutableSortedSet()
        Converts the RichIterable to the default ImmutableSortedSet implementation.
        Since:
        11.0

      • toImmutableSortedSet

        default ImmutableSortedSet<T> toImmutableSortedSet​(Comparator<? super T> comparator)
        Converts the collection to an ImmutableSortedSet implementation and sorts it using the specified comparator.
        Since:
        11.0

      • toImmutableSortedSetBy

        default <V extends Comparable<? super V>> ImmutableSortedSet<T> toImmutableSortedSetBy​(Function<? super T,​? extends V> function)
        Converts the collection to an ImmutableSortedSet implementation and sorts it based on the natural order of the attribute returned by function.
        Since:
        11.0

      • toImmutableSortedBag

        default ImmutableSortedBag<T> toImmutableSortedBag()
        Converts the RichIterable to the default ImmutableSortedBag implementation.
        Since:
        11.0

      • toImmutableSortedBag

        default ImmutableSortedBag<T> toImmutableSortedBag​(Comparator<? super T> comparator)
        Converts the collection to an ImmutableSortedBag implementation and sorts it using the specified comparator.
        Since:
        11.0

      • toImmutableSortedBagBy

        default <V extends Comparable<? super V>> ImmutableSortedBag<T> toImmutableSortedBagBy​(Function<? super T,​? extends V> function)
        Converts the collection to an ImmutableSortedBag implementation and sorts it based on the natural order of the attribute returned by function.
        Since:
        11.0

      • toImmutableMap

        default <NK,​NV> ImmutableMap<NK,​NV> toImmutableMap​(Function<? super T,​? extends NK> keyFunction,
                                                               Function<? super T,​? extends NV> valueFunction)
        Converts the collection to an ImmutableMap implementation using the specified key and value functions.
        Since:
        11.0

      • toImmutableBiMap

        default <NK,​NV> ImmutableBiMap<NK,​NV> toImmutableBiMap​(Function<? super T,​? extends NK> keyFunction,
                                                                   Function<? super T,​? extends NV> valueFunction)
        Converts the collection to an immutable BiMap implementation using the specified key and value functions.
        Since:
        11.0

      • asLazy

        LazyIterable<T> asLazy()
        Returns a lazy (deferred) iterable, most likely implemented by calling LazyIterate.adapt(this).
        Since:
        1.0.

      • toArray

        <E> E[] toArray​(E[] array)
        Converts this iterable to an array using the specified target array, assuming the target array is as long or longer than the iterable.
        Since:
        1.0
        See Also:
        Collection.toArray(Object[])

      • min

        T min​(Comparator<? super T> comparator)
        Returns the minimum element out of this container based on the comparator.
        Throws:
        NoSuchElementException - if the RichIterable is empty
        Since:
        1.0

      • max

        T max​(Comparator<? super T> comparator)
        Returns the maximum element out of this container based on the comparator.
        Throws:
        NoSuchElementException - if the RichIterable is empty
        Since:
        1.0

      • minOptional

        default Optional<T> minOptional​(Comparator<? super T> comparator)
        Returns the minimum element out of this container based on the comparator as an Optional. If the container is empty Optional.empty() is returned.
        Throws:
        NullPointerException - if the minimum element is null
        Since:
        8.2

      • maxOptional

        default Optional<T> maxOptional​(Comparator<? super T> comparator)
        Returns the maximum element out of this container based on the comparator as an Optional. If the container is empty Optional.empty() is returned.
        Throws:
        NullPointerException - if the maximum element is null
        Since:
        8.2

      • minBy

        <V extends Comparable<? super V>> T minBy​(Function<? super T,​? extends V> function)
        Returns the minimum elements out of this container based on the natural order of the attribute returned by Function.
        Throws:
        NoSuchElementException - if the RichIterable is empty
        Since:
        1.0

      • maxBy

        <V extends Comparable<? super V>> T maxBy​(Function<? super T,​? extends V> function)
        Returns the maximum elements out of this container based on the natural order of the attribute returned by Function.
        Throws:
        NoSuchElementException - if the RichIterable is empty
        Since:
        1.0

      • minByOptional

        default <V extends Comparable<? super V>> Optional<T> minByOptional​(Function<? super T,​? extends V> function)
        Returns the minimum elements out of this container based on the natural order of the attribute returned by Function as an Optional. If the container is empty Optional.empty() is returned.
        Throws:
        NullPointerException - if the minimum element is null
        Since:
        8.2

      • maxByOptional

        default <V extends Comparable<? super V>> Optional<T> maxByOptional​(Function<? super T,​? extends V> function)
        Returns the maximum elements out of this container based on the natural order of the attribute returned by Function as an Optional. If the container is empty Optional.empty() is returned.
        Throws:
        NullPointerException - if the maximum element is null
        Since:
        8.2

      • sumOfInt

        long sumOfInt​(IntFunction<? super T> function)
        Returns the final long result of evaluating function for each element of the iterable and adding the results together.
        Since:
        2.0

      • sumOfFloat

        double sumOfFloat​(FloatFunction<? super T> function)
        Returns the final double result of evaluating function for each element of the iterable and adding the results together. It uses Kahan summation algorithm to reduce numerical error.
        Since:
        2.0

      • sumOfLong

        long sumOfLong​(LongFunction<? super T> function)
        Returns the final long result of evaluating function for each element of the iterable and adding the results together.
        Since:
        2.0

      • sumOfDouble

        double sumOfDouble​(DoubleFunction<? super T> function)
        Returns the final double result of evaluating function for each element of the iterable and adding the results together. It uses Kahan summation algorithm to reduce numerical error.
        Since:
        2.0

      • summarizeInt

        default IntSummaryStatistics summarizeInt​(IntFunction<? super T> function)
        Returns the result of summarizing the value returned from applying the IntFunction to each element of the iterable. 
         IntSummaryStatistics stats =
     Lists.mutable.with(1, 2, 3).summarizeInt(Integer::intValue);
        Since:
        8.0

      • summarizeFloat

        default DoubleSummaryStatistics summarizeFloat​(FloatFunction<? super T> function)
        Returns the result of summarizing the value returned from applying the FloatFunction to each element of the iterable. 
         DoubleSummaryStatistics stats =
     Lists.mutable.with(1, 2, 3).summarizeFloat(Integer::floatValue);
        Since:
        8.0

      • summarizeLong

        default LongSummaryStatistics summarizeLong​(LongFunction<? super T> function)
        Returns the result of summarizing the value returned from applying the LongFunction to each element of the iterable. 
         LongSummaryStatistics stats =
     Lists.mutable.with(1, 2, 3).summarizeLong(Integer::longValue);
        Since:
        8.0

      • summarizeDouble

        default DoubleSummaryStatistics summarizeDouble​(DoubleFunction<? super T> function)
        Returns the result of summarizing the value returned from applying the DoubleFunction to each element of the iterable. 
         DoubleSummaryStatistics stats =
     Lists.mutable.with(1, 2, 3).summarizeDouble(Integer::doubleValue);
        Since:
        8.0

      • reduceInPlace

        default <R,​A> R reduceInPlace​(Collector<? super T,​A,​R> collector)
        This method produces the equivalent result as Stream.collect(Collector). 
         MutableObjectLongMap<Integer> map2 =
     Lists.mutable.with(1, 2, 3, 4, 5).reduceInPlace(Collectors2.sumByInt(i -> Integer.valueOf(i % 2), Integer::intValue));
        Since:
        8.0

      • sumByInt

        <V> ObjectLongMap<V> sumByInt​(Function<? super T,​? extends V> groupBy,
                              IntFunction<? super T> function)
        Groups and sums the values using the two specified functions.
        Since:
        6.0

      • sumByFloat

        <V> ObjectDoubleMap<V> sumByFloat​(Function<? super T,​? extends V> groupBy,
                                  FloatFunction<? super T> function)
        Groups and sums the values using the two specified functions.
        Since:
        6.0

      • sumByLong

        <V> ObjectLongMap<V> sumByLong​(Function<? super T,​? extends V> groupBy,
                               LongFunction<? super T> function)
        Groups and sums the values using the two specified functions.
        Since:
        6.0

      • sumByDouble

        <V> ObjectDoubleMap<V> sumByDouble​(Function<? super T,​? extends V> groupBy,
                                   DoubleFunction<? super T> function)
        Groups and sums the values using the two specified functions.
        Since:
        6.0

      • makeString

        default String makeString()
        Returns a string representation of this collection by delegating to makeString(String) and defaulting the separator parameter to the characters ", " (comma and space).
        Returns:
        a string representation of this collection.
        Since:
        1.0

      • makeString

        default String makeString​(String separator)
        Returns a string representation of this collection by delegating to makeString(String, String, String) and defaulting the start and end parameters to "" (the empty String).
        Returns:
        a string representation of this collection.
        Since:
        1.0

      • makeString

        default String makeString​(String start,
                          String separator,
                          String end)
        Returns a string representation of this collection with the elements separated by the specified separator and enclosed between the start and end strings.
        Returns:
        a string representation of this collection.
        Since:
        1.0

      • makeString

        default String makeString​(Function<? super T,​Object> function,
                          String start,
                          String separator,
                          String end)
        Returns a string representation of the collection, created by applying the function supplied to each element, with the elements separated by the specified separator and enclosed between the start and end strings.
        Returns:
        a string representation of the mapped collection

      • appendString

        default void appendString​(Appendable appendable)
        Prints a string representation of this collection onto the given Appendable. Prints the string returned by makeString().
        Since:
        1.0

      • appendString

        default void appendString​(Appendable appendable,
                          String separator)
        Prints a string representation of this collection onto the given Appendable. Prints the string returned by makeString(String).
        Since:
        1.0

      • groupBy

        <V> Multimap<V,​T> groupBy​(Function<? super T,​? extends V> function)
        For each element of the iterable, the function is evaluated and the results of these evaluations are collected into a new multimap, where the transformed value is the key and the original values are added to the same (or similar) species of collection as the source iterable.

        Example using a Java 8 method reference: 

         Multimap<String, Person> peopleByLastName =
     people.groupBy(Person::getLastName);
        Since:
        1.0

      • countBy

        default <V> Bag<V> countBy​(Function<? super T,​? extends V> function)
        This method will count the number of occurrences of each value calculated by applying the function to each element of the collection.
        Since:
        9.0

      • countBy

        default <V,​R extends MutableBagIterable<V>> R countBy​(Function<? super T,​? extends V> function,
                                                            R target)
        This method will count the number of occurrences of each value calculated by applying the function to each element of the collection.
        Since:
        9.0

      • countByWith

        default <V,​P> Bag<V> countByWith​(Function2<? super T,​? super P,​? extends V> function,
                                       P parameter)
        This method will count the number of occurrences of each value calculated by applying the function to each element of the collection with the specified parameter as the second argument.
        Since:
        9.0

      • countByWith

        default <V,​P,​R extends MutableBagIterable<V>> R countByWith​(Function2<? super T,​? super P,​? extends V> function,
                                                                        P parameter,
                                                                        R target)
        This method will count the number of occurrences of each value calculated by applying the function to each element of the collection with the specified parameter as the second argument.
        Since:
        9.0

      • countByEach

        default <V> Bag<V> countByEach​(Function<? super T,​? extends Iterable<V>> function)
        This method will count the number of occurrences of each value calculated by applying the function to each element of the collection.
        Since:
        10.0.0

      • countByEach

        default <V,​R extends MutableBagIterable<V>> R countByEach​(Function<? super T,​? extends Iterable<V>> function,
                                                                R target)
        This method will count the number of occurrences of each value calculated by applying the function to each element of the collection.
        Since:
        10.0.0

      • groupBy

        <V,​R extends MutableMultimap<V,​T>> R groupBy​(Function<? super T,​? extends V> function,
                                                         R target)
        Same as groupBy(Function), except that the results are gathered into the specified target multimap.

        Example using a Java 8 method reference: 

         FastListMultimap<String, Person> peopleByLastName =
     people.groupBy(Person::getLastName, new FastListMultimap<String, Person>());
        Since:
        1.0

      • groupByEach

        <V> Multimap<V,​T> groupByEach​(Function<? super T,​? extends Iterable<V>> function)
        Similar to groupBy(Function), except the result of evaluating function will return a collection of keys for each value.
        Since:
        1.0

      • groupByUniqueKey

        <V> MapIterable<V,​T> groupByUniqueKey​(Function<? super T,​? extends V> function)
        For each element of the iterable, the function is evaluated, and the results of these evaluations are collected into a new map, where the transformed value is the key. The generated keys must each be unique, or else an exception is thrown.
        Throws:
        IllegalStateException - if the keys returned by the function are not unique
        Since:
        5.0
        See Also:
        groupBy(Function)

      • toString

        String toString()
        Returns a string with the elements of this iterable separated by commas with spaces and enclosed in square brackets. 
         Assert.assertEquals("[]", Lists.mutable.empty().toString());
 Assert.assertEquals("[1]", Lists.mutable.with(1).toString());
 Assert.assertEquals("[1, 2, 3]", Lists.mutable.with(1, 2, 3).toString());
        Overrides:
        toString in class Object
        Returns:
        a string representation of this RichIterable
        Since:
        1.0
        See Also:
        AbstractCollection.toString()

      • zip

        @Deprecated
<S> RichIterable<Pair<T,​S>> zip​(Iterable<S> that)
        Deprecated.
        in 6.0. Use OrderedIterable.zip(Iterable) instead.
        Returns a RichIterable formed from this RichIterable and another RichIterable by combining corresponding elements in pairs. If one of the two RichIterables is longer than the other, its remaining elements are ignored.
        Type Parameters:
        S - the type of the second half of the returned pairs
        Parameters:
        that - The RichIterable providing the second half of each result pair
        Returns:
        A new RichIterable containing pairs consisting of corresponding elements of this RichIterable and that. The length of the returned RichIterable is the minimum of the lengths of this RichIterable and that.
        Since:
        1.0

      • chunk

        RichIterable<RichIterable<T>> chunk​(int size)
        Partitions elements in fixed size chunks.
        Parameters:
        size - the number of elements per chunk
        Returns:
        A RichIterable containing RichIterables of size size, except the last will be truncated if the elements don't divide evenly.
        Since:
        1.0

      • aggregateInPlaceBy

        default <K,​V> MapIterable<K,​V> aggregateInPlaceBy​(Function<? super T,​? extends K> groupBy,
                                                              Function0<? extends V> zeroValueFactory,
                                                              Procedure2<? super V,​? super T> mutatingAggregator)
        Applies an aggregate procedure over the iterable grouping results into a Map based on the specific groupBy function. Aggregate results are required to be mutable as they will be changed in place by the procedure. A second function specifies the initial "zero" aggregate value to work with (i.e. new AtomicInteger(0)).
        Since:
        3.0

      • aggregateBy

        default <K,​V> MapIterable<K,​V> aggregateBy​(Function<? super T,​? extends K> groupBy,
                                                       Function0<? extends V> zeroValueFactory,
                                                       Function2<? super V,​? super T,​? extends V> nonMutatingAggregator)
        Applies an aggregate function over the iterable grouping results into a map based on the specific groupBy function. Aggregate results are allowed to be immutable as they will be replaced in place in the map. A second function specifies the initial "zero" aggregate value to work with (i.e. Integer.valueOf(0)).
        Since:
        3.0

      • aggregateBy

        default <K,​V,​R extends MutableMapIterable<K,​V>> R aggregateBy​(Function<? super T,​? extends K> groupBy,
                                                                                Function0<? extends V> zeroValueFactory,
                                                                                Function2<? super V,​? super T,​? extends V> nonMutatingAggregator,
                                                                                R target)
        Applies an aggregate function over the iterable grouping results into the target map based on the specific groupBy function. Aggregate results are allowed to be immutable as they will be replaced in place in the map. A second function specifies the initial "zero" aggregate value to work with (i.e. Integer.valueOf(0)).
        Since:
        10.3

      • groupByAndCollect

        default <K,​V,​R extends MutableMultimap<K,​V>> R groupByAndCollect​(Function<? super T,​? extends K> groupByFunction,
                                                                                   Function<? super T,​? extends V> collectFunction,
                                                                                   R target)
        Applies a groupBy function over the iterable, followed by a collect function.
        Parameters:
        groupByFunction - a Function to use as the groupBy transformation function
        collectFunction - a Function to use as the collect transformation function
        Returns:
        The target collection where the key is the transformed result from applying the groupBy function and the value is the transformed result from applying the collect function.
        Since:
        10.1.0
        See Also:
        groupBy(Function), Multimap.collectValues(Function)