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 a=new ArrayList         


        

Answer 1

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<MyBean> deleteCandidates = new ArrayList<>();
 List<MyBean> 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);
 }

Answer 2

Snippet to remove a element from any arraylist based on the matching condition is as follows:

List<String> nameList = new ArrayList<>();
        nameList.add("Arafath");
        nameList.add("Anjani");
        nameList.add("Rakesh");

Iterator<String> myItr = nameList.iterator();

    while (myItr.hasNext()) {
        String name = myItr.next();
        System.out.println("Next name is: " + name);
        if (name.equalsIgnoreCase("rakesh")) {
            myItr.remove();
        }
    }

Answer 3

This will give you the output,

    ArrayList<String> l= new ArrayList<String>();

    String[] str={"16","b","c","d","e","16","f","g","16","b"};
    ArrayList<String> tempList= new ArrayList<String>();

    for(String s:str){
        l.add(s);
    }

    ArrayList<String> duplicates= new ArrayList<String>();

    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]

Answer 4

for java8 we can simply use removeIf function like this

listValues.removeIf(value -> value.type == "Deleted");

Answer 5

Try below code :

 public static void main(String[] args) throws Exception{
     List<String> l = new ArrayList<String>();
     l.add("abc");
     l.add("xyz");
     l.add("test");
     l.add("test123");
     System.out.println(l);
     List<String> dl = new ArrayList<String>();
    for (int i = 0; i < 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]

Answer 6

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.