How to remove element from ArrayList by checking its value

Question

I have ArrayList  from which I want to remove an element which has particular value     for eg    ArrayList lt String gt  a new ArrayList lt String gt     a add  abcd    a add  acbd    a add  dbca      I know we can iterate over arraylist  and  remove   method to remove element but I dont know how to do it while iterating  How can I remove element which has value  acbd   that is second element

User · Answer

Snippet to remove a element from any arraylist based on the matching condition is as follows   List lt String gt  nameList   new ArrayList lt  gt             nameList add  Arafath            nameList add  Anjani            nameList add  Rakesh     Iterator lt String gt  myItr   nameList iterator         while  myItr hasNext              String name   myItr next            System out println  Next name is      name           if  name equalsIgnoreCase  rakesh                  myItr remove

User · Answer

use contains   method which is available in list interface to check the value exists in list or not If it contains that element  get its index and remove it

User · Answer

for java8 we can simply use removeIf function like this  listValues removeIf value - gt  value type     Deleted

User · Answer

In your case  there s no need to iterate through the list  because you know which object to delete  You have several options  First you can remove the object by index  so if you know  that the object is the second list element     a remove 1            indexes are zero-based   Then  you can remove the first occurence of your string    a remove  acbd        removes the first String object that is equal to the                        String represented by this literal   Or  remove all strings with a certain value    while a remove  acbd         It s a bit more complicated  if you have more complex objects in your collection and want to remove instances  that have a certain property  So that you can t remove them by using remove with an object that is equal to the one you want to delete   In those case  I usually use a second list to collect all instances that I want to delete and remove them in a second pass    List lt MyBean gt  deleteCandidates   new ArrayList lt  gt      List lt MyBean gt  myBeans   getThemFromSomewhere         Pass 1 - collect delete candidates  for  MyBean myBean   myBeans        if  shallBeDeleted myBean            deleteCandidates add myBean                 Pass 2 - delete  for  MyBean deleteCandidate   deleteCandidates        myBeans remove deleteCandidate

User · Answer

Just use myList remove myObject    It uses the equals method of the class  See http   docs oracle com javase 6 docs api java util List html remove java lang Object   BTW  if you have more complex things to do  you should check out the guava library that has dozen of utility to do that with predicates and so on

User · Answer

Use a iterator to loop through list and then delete the required object       Iterator itr   a iterator        while itr hasNext             if itr next   equals  acbd                itr remove

User · Answer

You would need to use an Iterator like so   Iterator lt String gt  iterator   a iterator    while iterator hasNext          String value   iterator next        if   abcd  equals value                 iterator remove            break            That being said  you can use the remove int index  or remove Object obj  which are provided by the ArrayList class  Note however  that calling these methods while you are iterating over the loop  will cause a ConcurrentModificationException  so this will not work   for String str   a        if  str equals  acbd                 a remove  abcd            break            But this will  since you are not iterating over the contents of the loop    a remove  acbd      If you have more complex objects you would need to override the equals method

User · Answer

This will give you the output       ArrayList lt String gt  l  new ArrayList lt String gt          String   str   16   b   c   d   e   16   f   g   16   b        ArrayList lt String gt  tempList  new ArrayList lt String gt          for String s str           l add s              ArrayList lt String gt  duplicates  new ArrayList lt String gt          for  String dupWord   l            if   tempList contains dupWord                 tempList add dupWord            else              duplicates add dupWord                        for String check   duplicates           if tempList contains check                tempList remove check                        System out println tempList     output    c  d  e  f  g

User · Answer

Try below code      public static void main String   args  throws Exception       List lt String gt  l   new ArrayList lt String gt          l add  abc         l add  xyz         l add  test         l add  test123         System out println l        List lt String gt  dl   new ArrayList lt String gt         for  int i   0  i  lt  l size    i               String a   l get i            System out println a             if a equals  test                  dl add a                        l removeAll dl        System out println l        your output       abc  xyz  test  test123  abc xyz test test123  abc  xyz  test123

User · Answer

One-liner  java8    list removeIf s - gt  s equals  acbd        removes all instances  not just the 1st one    does all the iterating implicitly

User · Answer

You should check API for these questions   You can use remove methods   a remove 1     OR  a remove  acbd

[java] How to remove element from ArrayList by checking its value?

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