List

add

abstract fun add(element: E): Boolean

Appends the specified element to the end of this list (optional operation).

Lists that support this operation may place limitations on what elements may be added to this list. In particular, some lists will refuse to add null elements, and others will impose restrictions on the type of elements that may be added. List classes should clearly specify in their documentation any restrictions on what elements may be added.

add

abstract fun add(
    index: Int, 
    element: E
): Unit

Inserts the specified element at the specified position in this list (optional operation). Shifts the element currently at that position (if any) and any subsequent elements to the right (adds one to their indices).

addAll

abstract fun addAll(elements: Collection<E>): Boolean

Appends all of the elements in the specified collection to the end of this list, in the order that they are returned by the specified collection's iterator (optional operation). The behavior of this operation is undefined if the specified collection is modified while the operation is in progress. (Note that this will occur if the specified collection is this list, and it's nonempty.)

addAll

abstract fun addAll(
    index: Int, 
    c: MutableCollection<out E>
): Boolean

Inserts all of the elements in the specified collection into this list at the specified position (optional operation). Shifts the element currently at that position (if any) and any subsequent elements to the right (increases their indices). The new elements will appear in this list in the order that they are returned by the specified collection's iterator. The behavior of this operation is undefined if the specified collection is modified while the operation is in progress. (Note that this will occur if the specified collection is this list, and it's nonempty.)

clear

abstract fun clear(): Unit

Removes all of the elements from this list (optional operation). The list will be empty after this call returns.

contains

abstract fun contains(element: E?): Boolean

Returns true if this list contains the specified element. More formally, returns true if and only if this list contains at least one element e such that Objects.equals(o, e).

containsAll

abstract fun containsAll(elements: Collection<E>): Boolean

Returns true if this list contains all of the elements of the specified collection.

copyOf

open static fun <E : Any!> copyOf(coll: MutableCollection<out E>): MutableList<E>

Returns an unmodifiable List containing the elements of the given Collection, in its iteration order. The given Collection must not be null, and it must not contain any null elements. If the given Collection is subsequently modified, the returned List will not reflect such modifications.

get

abstract fun get(index: Int): E

Returns the element at the specified position in this list.

indexOf

abstract fun indexOf(o: Any?): Int

Returns the index of the first occurrence of the specified element in this list, or -1 if this list does not contain the element. More formally, returns the lowest index i such that Objects.equals(o, get(i)), or -1 if there is no such index.

isEmpty

abstract fun isEmpty(): Boolean

Returns true if this list contains no elements.

iterator

abstract fun iterator(): MutableIterator<E>

Returns an iterator over the elements in this list in proper sequence.

lastIndexOf

abstract fun lastIndexOf(o: Any?): Int

Returns the index of the last occurrence of the specified element in this list, or -1 if this list does not contain the element. More formally, returns the highest index i such that Objects.equals(o, get(i)), or -1 if there is no such index.

listIterator

abstract fun listIterator(): MutableListIterator<E>

Returns a list iterator over the elements in this list (in proper sequence).

listIterator

abstract fun listIterator(index: Int): MutableListIterator<E>

Returns a list iterator over the elements in this list (in proper sequence), starting at the specified position in the list. The specified index indicates the first element that would be returned by an initial call to next. An initial call to previous would return the element with the specified index minus one.

of

open static fun <E : Any!> of(): MutableList<E>

Returns an unmodifiable list containing zero elements. See Unmodifiable Lists for details.

of

open static fun <E : Any!> of(e1: E): MutableList<E>

Returns an unmodifiable list containing one element. See Unmodifiable Lists for details.

of

open static fun <E : Any!> of(
    e1: E, 
    e2: E
): MutableList<E>

Returns an unmodifiable list containing two elements. See Unmodifiable Lists for details.

of

open static fun <E : Any!> of(
    e1: E, 
    e2: E, 
    e3: E
): MutableList<E>

Returns an unmodifiable list containing three elements. See Unmodifiable Lists for details.

of

open static fun <E : Any!> of(
    e1: E, 
    e2: E, 
    e3: E, 
    e4: E
): MutableList<E>

Returns an unmodifiable list containing four elements. See Unmodifiable Lists for details.

of

open static fun <E : Any!> of(
    e1: E, 
    e2: E, 
    e3: E, 
    e4: E, 
    e5: E
): MutableList<E>

Returns an unmodifiable list containing five elements. See Unmodifiable Lists for details.

of

open static fun <E : Any!> of(
    e1: E, 
    e2: E, 
    e3: E, 
    e4: E, 
    e5: E, 
    e6: E
): MutableList<E>

Returns an unmodifiable list containing six elements. See Unmodifiable Lists for details.

of

open static fun <E : Any!> of(
    e1: E, 
    e2: E, 
    e3: E, 
    e4: E, 
    e5: E, 
    e6: E, 
    e7: E
): MutableList<E>

Returns an unmodifiable list containing seven elements. See Unmodifiable Lists for details.

of

open static fun <E : Any!> of(
    e1: E, 
    e2: E, 
    e3: E, 
    e4: E, 
    e5: E, 
    e6: E, 
    e7: E, 
    e8: E
): MutableList<E>

Returns an unmodifiable list containing eight elements. See Unmodifiable Lists for details.

of

open static fun <E : Any!> of(
    e1: E, 
    e2: E, 
    e3: E, 
    e4: E, 
    e5: E, 
    e6: E, 
    e7: E, 
    e8: E, 
    e9: E
): MutableList<E>

Returns an unmodifiable list containing nine elements. See Unmodifiable Lists for details.

of

open static fun <E : Any!> of(
    e1: E, 
    e2: E, 
    e3: E, 
    e4: E, 
    e5: E, 
    e6: E, 
    e7: E, 
    e8: E, 
    e9: E, 
    e10: E
): MutableList<E>

Returns an unmodifiable list containing ten elements. See Unmodifiable Lists for details.

of

@SafeVarargs open static fun <E : Any!> of(vararg elements: E): MutableList<E>

Returns an unmodifiable list containing an arbitrary number of elements. See Unmodifiable Lists for details.

remove

abstract fun remove(index: Int): E

Removes the element at the specified position in this list (optional operation). Shifts any subsequent elements to the left (subtracts one from their indices). Returns the element that was removed from the list.

remove

abstract fun remove(element: E?): Boolean

Removes the first occurrence of the specified element from this list, if it is present (optional operation). If this list does not contain the element, it is unchanged. More formally, removes the element with the lowest index i such that Objects.equals(o, get(i)) (if such an element exists). Returns true if this list contained the specified element (or equivalently, if this list changed as a result of the call).

removeAll

abstract fun removeAll(elements: Collection<E>): Boolean

Removes from this list all of its elements that are contained in the specified collection (optional operation).

replaceAll

open fun replaceAll(operator: UnaryOperator<E>): Unit

Replaces each element of this list with the result of applying the operator to that element. Errors or runtime exceptions thrown by the operator are relayed to the caller.

retainAll

abstract fun retainAll(elements: Collection<E>): Boolean

Retains only the elements in this list that are contained in the specified collection (optional operation). In other words, removes from this list all of its elements that are not contained in the specified collection.

set

abstract fun set(
    index: Int, 
    element: E
): E

Replaces the element at the specified position in this list with the specified element (optional operation).

sort

open fun sort(c: Comparator<in E>?): Unit

Sorts this list according to the order induced by the specified Comparator.

All elements in this list must be mutually comparable using the specified comparator (that is, c.compare(e1, e2) must not throw a ClassCastException for any elements e1 and e2 in the list).

If the specified comparator is null then all elements in this list must implement the Comparable interface and the elements' natural ordering should be used.

This list must be modifiable, but need not be resizable.

For apps running on and targeting Android versions greater than Nougat (API level > 25), Collections#sort(List) delegates to this method. Such apps must not call Collections#sort(List) from this method. Instead, prefer not overriding this method at all. If you must override it, consider this implementation:

@Override
  public void sort(Comparator<? super E> c) {
    Object[] elements = toArray();
    Arrays.sort(elements, c);
    ListIterator<E> iterator = (ListIterator<Object>) listIterator();
    for (Object element : elements) {
      iterator.next();
      iterator.set((E) element);
    }
  }
  

spliterator

open fun spliterator(): Spliterator<E>

Creates a Spliterator over the elements in this list.

The Spliterator reports Spliterator#SIZED and Spliterator#ORDERED. Implementations should document the reporting of additional characteristic values.

subList

abstract fun subList(
    fromIndex: Int, 
    toIndex: Int
): MutableList<E>

Returns a view of the portion of this list between the specified fromIndex, inclusive, and toIndex, exclusive. (If fromIndextoIndex are equal, the returned list is empty.) The returned list is backed by this list, so non-structural changes in the returned list are reflected in this list, and vice-versa. The returned list supports all of the optional list operations supported by this list.

This method eliminates the need for explicit range operations (of the sort that commonly exist for arrays). Any operation that expects a list can be used as a range operation by passing a subList view instead of a whole list. For example, the following idiom removes a range of elements from a list:

<code>list.subList(from, to).clear();
  </code>

The semantics of the list returned by this method become undefined if the backing list (i.e., this list) is structurally modified in any way other than via the returned list. (Structural modifications are those that change the size of this list, or otherwise perturb it in such a fashion that iterations in progress may yield incorrect results.)

toArray

abstract fun toArray(): Array<Any!>

Returns an array containing all of the elements in this list in proper sequence (from first to last element).

The returned array will be "safe" in that no references to it are maintained by this list. (In other words, this method must allocate a new array even if this list is backed by an array). The caller is thus free to modify the returned array.

This method acts as bridge between array-based and collection-based APIs.

toArray

abstract fun <T : Any!> toArray(a: Array<T>): Array<T>

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. If the list fits in the specified array, it is returned therein. Otherwise, a new array is allocated with the runtime type of the specified array and the size of this list.

If the list fits in the specified array with room to spare (i.e., the array has more elements than the list), the element in the array immediately following the end of the list is set to null. (This is useful in determining the length of the list only if the caller knows that the list does not contain any null elements.)

Like the toArray() method, this method acts as bridge between array-based and collection-based APIs. Further, this method allows precise control over the runtime type of the output array, and may, under certain circumstances, be used to save allocation costs.

Suppose x is a list known to contain only strings. The following code can be used to dump the list into a newly allocated array of String:

<code>String[] y = x.toArray(new String[0]);
  </code>

size

abstract val size: Int

Returns the number of elements in this list. If this list contains more than Integer.MAX_VALUE elements, returns Integer.MAX_VALUE.