Remove Item from ArrayList

Question

I have an ArrayList suppose list  and it has 8 items A-H and now I want to delete 1 3 5 position Item stored in int array from the list how can I do this   I am trying to do this with   ArrayList lt String gt  list   new ArrayList lt String gt     list add  A    list add  B    list add  C    list add  D    list add  E    list add  F    list add  G    list add  H     int i      1 3 5    for  int j   0  j  lt  i length  j          list remove i j        But after first item deleted positioned of array is changed and in the next iterate it deletes wrong element or give exception

User · Answer

If you use      a replica is created for the original arraylist in the second one  but the reference is same so if you change in one list   the other one will also get modified  Use this instead of              List Of Array1 addAll List Of Array

User · Answer

How about this  Just give it a thought-  import java util ArrayList   class Solution           public static void main  String   args                 ArrayList lt String gt  List Of Array   new ArrayList lt String gt                  List Of Array add  A                 List Of Array add  B                 List Of Array add  C                 List Of Array add  D                 List Of Array add  E                 List Of Array add  F                 List Of Array add  G                 List Of Array add  H                  int i      1 3 5                 for  int j   0  j  lt  i length  j                       List Of Array remove i j -j                                System out println List Of Array                    And the output was-   A  C  E  G  H

User · Answer

Try it this way   ArrayList lt String gt  List Of Array   new ArrayList lt String gt     List Of Array add  A    List Of Array add  B    List Of Array add  C    List Of Array add  D    List Of Array add  E    List Of Array add  F    List Of Array add  G    List Of Array add  H     int i      5 3 1    for  int j   0  j  lt  i length  j          List Of Array remove i j

User · Answer

public void DeleteUserIMP UserIMP useriamp           synchronized  ListUserIMP                if  ListUserIMP isEmpty                  System out println  user is empty               else               Iterator lt UserIMP gt  it   ListUserIMP iterator                while  it hasNext                      UserIMP user   it next                    if  useriamp getMoblieNumber   equals user getMoblieNumber                           it remove                        System out println  remove it                                                   ListUserIMP remove useriamp                System out println   this user removed                      Constants RESULT FOR REGISTRATION   Constants MESSAGE OK             System out println  This user Deleted     Constants MESSAGE OK

User · Answer

In this specific case  you should remove the elements in descending order  First index 5  then 3  then 1  This will remove the elements from the list without undesirable side effects   for  int j   i length-1  j  gt   0  j--        list remove i j

User · Answer

You can remove elements from ArrayList using ListIterator   ListIterator listIterator   List Of Array listIterator         Use void remove   method of ListIterator to remove an element from List       It removes the last element returned by next or previous methods      listIterator next       remove element returned by last next method listIterator remove     remove element at 1st position listIterator next    listIterator next    listIterator remove     remove element at 3rd position listIterator next    listIterator next    listIterator remove     remove element at 5th position

User · Answer

As mentioned before  iterator remove     is maybe the only safe way to remove list items during the loop   For deeper understanding of items removal using the iterator  try to look at this thread

User · Answer

String   mString   new String     B    D    F     for  int j   0  j  lt  mString length-1  j              List Of Array remove mString j

User · Answer

remove int index  method of arraylist removes the element at the specified position index  in the list  After removing arraylist items shifts any subsequent elements to the left   Means if a arraylist contains  20 15 30 40   I have called the method  arraylist remove 1   then the data 15 will be deleted and 30  amp  40 these two items will be left shifted by 1   For this reason you have to delete higher index item of arraylist first   So  for your given situation  the code will be    ArrayList lt String gt  list   new ArrayList lt String gt     list add  A    list add  B    list add  C    list add  D    list add  E    list add  F    list add  G    list add  H     int i      1 3 5    for  int j   i length-1  j  gt   0  j--        list remove i j

User · Answer

I assume the array i is ascend sorted  here is another solution with Iterator  it is more generic   ArrayList lt String gt  list   new ArrayList lt String gt     list add  A    list add  B    list add  C    list add  D    list add  E    list add  F    list add  G    list add  H     int i      1 3 5    Iterator lt String gt  itr   list iterator    int pos   0  int index   0  while  itr hasNext          itr next        if  pos  gt   i length            break            if  i pos     index            itr remove            pos               index

[java] Remove Item from ArrayList

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