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List

API

Note

Here, I have listed some commonly used methods. For the complete methods, please refer to Javadocs

Class ArrayList<E>

Warning

ArrayList is not array! (ArrayList<E> <: List<E>)

Constructors

  • ArrayList(): Constructs an empty list with an initial capacity of ten.
  • ArrayList(Collection<? extends E> c): Constructs a list containing the elements of the specified collection, in the order they are returned by the collection's iterator.
  • ArrayList(int initialCapacity): Constructs an empty list with the specified initial capacity.

Method

  • void clear(): Removes all of the elements from this list.
  • boolean isEmpty()
  • boolean contains(Object o)
  • E get(int index)
  • int size()
  • void sort(Comparator<? super E> c): sort the list in \(O(N\log N)\) time
  • E set(int index, E element): Replaces the element at the specified position in this list with the specified element.
  • boolean add(E e): Appends the specified element to the end of this list.
  • void add(int index, E element)
  • boolean addAll(Collection<? extends E> c)
  • boolean addAll(int index, Collection<? extends E> c): Inserts all of the elements in the specified collection into this list, starting at the specified position.
  • void forEach(Consumer<? super E> action): Performs the given action for each element of the Iterable until all elements have been processed or the action throws an exception.
  • int indexOf(Object o): Returns the index of the first occurrence of the specified element in this list, or -1 if this list does not contain the element.
  • int lastIndexOf(Object o): Returns the index of the last occurrence of the specified element in this list, or -1 if this list does not contain the element.
  • E remove(int index): Removes the element at the specified position in this list.
  • boolean remove(Object o): Removes the first occurrence of the specified element from this list, if it is present.
  • boolean removeAll(Collection<?> c): Removes from this list all of its elements that are contained in the specified collection.
  • boolean removeIf(Predicate<? super E> filter): Removes all of the elements of this collection that satisfy the given predicate.
  • protected void removeRange(int fromIndex, int toIndex): Removes from this list all of the elements whose index is between fromIndex, inclusive, and toIndex, exclusive.
  • List<E> subList(int fromIndex, int toIndex): Returns a view of the portion of this list between the specified fromIndex, inclusive, and toIndex, exclusive.
  • Object[] toArray(): Returns an array containing all of the elements in this list in proper sequence (from first to last element).
  • <T> T[] toArray(T[] a): Returns an array containing all of the elements in this list in proper sequence (from first to last element); the runtime type of the returned array is that of the specified array.
  • Object clone(): Returns a shallow copy of this ArrayList instance.
  • void ensureCapacity(int minCapacity): Increases the capacity of this ArrayList instance, if necessary, to ensure that it can hold at least the number of elements specified by the minimum capacity argument.

Reference