removing an element from String array in android

Question

Am doing a simple android application.In that I am deleting an element from array using the following code.

 arr_fav = {"1","2","3"};
 for(int i= 0;i<arr_fav.length;i++)
 {
     if(current_id == Integer.parseInt(arr_fav[i]))
     {
        arr_fav[1] = null;
     } }

By doing this am getting the array like arr_fav = {"1",null,"3"}.But I want like arr_fav = {"1","3"}.How to delete an element.Am new to this android development.Please help me to solve this.

Solution 1

its better to use arraylist

arr_fav = {"1","2","3"};
List<String> numlist = new ArrayList<String>();
for(int i= 0;i<arr_fav.length;i++)
{
 if(current_id == Integer.parseInt(arr_fav[i]))
 {
   // No operation here 
 }
 else
 {
     numlist.add(arr_fav[i]);
 }
}
 arr_fav = numlist .toArray(new String[numlist .size()]);

Solution 2

You don't.

Arrays can not be resized.

You would need to create a new (smaller) array, and copy the elements you wished to preserve into it.

A better Idea would be to use a List implementation that was dynamic. An ArrayList<Integer> for example.

Solution 3

Arrays in Java are not dynamic, you can use an ArrayList instead.

Solution 4

You can copy the array elements that you want into a new array

 j = 0;
 for(int i= 0;i<arr_fav.length;i++)
  {
   if(current_id != Integer.parseInt(arr_fav[i]))
 {
    arr_new[j++] = arr_fav[i];
 } }

Solution 5

Use an ArrayList instead of an array. It supports features like deleting any element, dynamic size, and many more.

ArrayList<String> arr_fav_list = new ArrayList<String>();
arr_fav_list.addAll(arr_fav);
arr_fav_list.remove(1);

View more solutions

Comments

[Mikhaili]

You can convert it to arraylist

[Mikhaili]

if you need something more general stackoverflow.com/a/122207/619713

[Mikhaili]

Optimization Parse one time current_id to string and equal it to arr_fav[i]

[amit]

-1 for "a List which is dynamic". The List interface does not require it being dynamic, it can even be immutable.

[Brian Roach]

THank you Mr. pedantic. I guess "of some sort which would be dynamic" wasn't clear enough? Nevermind, I'll edit it just for you.

[Ram kiran Pachigolla]

this is not exact answer. as he is checking the current_id with in array.

[The111]

It is indeed better to use an array list, but the way you're using it does not utilize any of its advantages. In your code above, numlist could be an array.

[amit]

At least be honest. A previous version of the answer was exactly as I cited, and not "that would be..." if you later edited it, it's a different story. Long story short - my comment +downvote did exactly what it should have been - made you change the answer to something more accurate.

[The111]

No, it is not an exact answer. It's an illustration how to use the remove() method of ArrayList, clearly.

[Ram kiran Pachigolla]

@The111, Here i am using arraylist instead of resizing array, as java does not provide resizing of its array by default. please check it carefuylly

[Brian Roach]

Dear lord, I was editing when you commented, which was about 30 seconds after I posted the revision you're complaining about. Nevermind that without trying to be Ranger Rick you could simply have said "Hey, that's not exactly correct".

[The111]

Yes, but the only feature of the ArrayList you're using is add(). If you're just going to add things one by one to the end of a list, you can use a simple array. The OP wanted to remove something from the middle of a list. Iterating through the entire list and putting everything but the deleted item into a new list is not a solution that requires or takes advantage of the ArrayList functionality.

[Mikhaili]

it's internal class com.android.internal.util.ArrayUtils

[Mikhaili]

Ah Ok but i think he develops for Android

[Nirav Tukadiya]

check out my code.if you have more element you should use variables for swapping elements.

[Mikhaili]

1. arr_fav is string array and you remove integer

[xagyg]

Thanks for the tip. Updated to use String.valueOf.

[Brian Roach]

@Madhumitha - Yes it "works", but you really should read the above comment.