Several arraylist operations

1. Delete the arraylist set Element

When deleting elements in the arraylist set, the clear, remove, rmoveat, and removerange methods are provided.

The clear method removes all elements.

Ref: int [] arr = new int [] {1, 2, 3, 4, 5, 6 };

Arraylist list = new arraylist (ARR );

List. Clear ();

2. Remove Method

This method is used to remove a specific object from the arraylistFirst match

Ref: int arr = new int [] {1, 2, 3, 4, 5, 6 };

Arraylist list = new arraylist (ARR );

List. Remove (3 );

3. removeat Method

Used to remove the elements of the specified index in the arraylist.

Ref:

Int arr = new int [] {1, 2, 3, 4, 5, 6 };

Arraylist list = new arraylist (ARR );

List. removeat (3 );

4. removerange Method

This method is used to remove a certain range of elements from the arraylist.

Ref: int [] arr = new int [] {1, 2, 3, 4, 5, 6 };

Arraylist list = new arraylist (ARR );

List. removerange (3, 2 );

Search for arraylist set Elements

You can use the contain method, indexof method, and lastindexof method provided by the arraylist class.

1. contian Method

Used to determine whether an element is in the arraylist set.

2. indexof Method

Returns the index of the first matching item in the entire arraylist starting from scratch.

3. lastindexof Method

Returns the index of the last matching item in the entire arraylist starting from scratch.

 

Several arraylist operations