Remove a specific string from an array of string

Question

I have an array like this:

String n[] = {\"google\",\"microsoft\",\"apple\"};

What I want to do is to remove \"apple\".

My problem

Answer 1

You can't remove anything from an array - they're always fixed length. Once you've created an array of length 3, that array will always have length 3.

You'd be better off with a List<String>, e.g. an ArrayList<String>:

List<String> list = new ArrayList<String>();
list.add("google");
list.add("microsoft");
list.add("apple");
System.out.println(list.size()); // 3

list.remove("apple");
System.out.println(list.size()); // 2

Collections like this are generally much more flexible than working with arrays directly.

EDIT: For removal:

void removeRandomElement(List<?> list, Random random)
{
    int index = random.nextInt(list.size());
    list.remove(index);
}

Answer 2

Define "remove".

Arrays are fixed length and can not be resized once created. You can set an element to null to remove an object reference;

for (int i = 0; i < myStringArray.length(); i++)
{
    if (myStringArray[i].equals(stringToRemove))
    {
        myStringArray[i] = null;
        break;
    }
}

or

myStringArray[indexOfStringToRemove] = null;

If you want a dynamically sized array where the object is actually removed and the list (array) size is adjusted accordingly, use an ArrayList<String>

myArrayList.remove(stringToRemove); 

or

myArrayList.remove(indexOfStringToRemove);

Edit in response to OP's edit to his question and comment below

String r = myArrayList.get(rgenerator.nextInt(myArrayList.size()));

Answer 3

It is not possible in on step or you need to keep the reference to the array. If you can change the reference this can help:

      String[] n = new String[]{"google","microsoft","apple"};
      final List<String> list =  new ArrayList<String>();
      Collections.addAll(list, n); 
      list.remove("apple");
      n = list.toArray(new String[list.size()]);

I not recommend the following but if you worry about performance:

      String[] n = new String[]{"google","microsoft","apple"};
      final String[] n2 = new String[2]; 
      System.arraycopy(n, 0, n2, 0, n2.length);
      for (int i = 0, j = 0; i < n.length; i++)
      {
        if (!n[i].equals("apple"))
        {
          n2[j] = n[i];
          j++;
        }      
      }

I not recommend it because the code is a lot more difficult to read and maintain.

Answer 4

import java.util.*;

class Array {
    public static void main(String args[]) {
        ArrayList al = new ArrayList();
        al.add("google");
        al.add("microsoft");
        al.add("apple");
        System.out.println(al);
        //i only remove the apple//
        al.remove(2);
        System.out.println(al);
    }
}

Answer 5

Arrays in Java aren't dynamic, like collection classes. If you want a true collection that supports dynamic addition and deletion, use ArrayList<>. If you still want to live with vanilla arrays, find the index of string, construct a new array with size one less than the original, and use System.arraycopy() to copy the elements before and after. Or write a copy loop with skip by hand, on small arrays the difference will be negligible.