CODEWITHSUNDEEP
javaarrayscharacter
GES Vadamanappakkam
GES Vadamanappakkam

Reputation: 55

Remove specific index from array in java

Can I remove a specific element from array by mentioning index value? For example can I remove the character d by giving index value 1?

char[] words = { 'c', 'd', 'f', 'h', 'j' };

Upvotes: 3

Views: 18858

Answers (6)

smac89
smac89

Reputation: 43224

Using String class:

char[] words = { 'c', 'd', 'f', 'h', 'j' };
String str = new String(words);
words = (str.substring(0, Math.min(1, words.length)) + str.substring(Math.min(1 + 1, words.length))).toCharArray();

Running in jshell:

jshell> char[] words = { 'c', 'd', 'f', 'h', 'j' };
words ==> char[5] { 'c', 'd', 'f', 'h', 'j' }

jshell> String str = new String(words);
str ==> "cdfhj"

jshell> words = (str.substring(0, Math.min(1, words.length)) + str.substring(Math.min(1 + 1, words.length))).toCharArray();
words ==> char[4] { 'c', 'f', 'h', 'j' }

jshell>

Upvotes: 0

Messi
Messi

Reputation: 25

 import java.util.Arrays;
  public class Main
 {
 public static void main(String[] args) {
 int[] my_array = {25, 14, 56, 15, 36, 56, 77, 18, 29, 49};

 int removeIndex = 1;
 int j=0;
  for(int i = 0; i < my_array.length -1; i++)
  {

    if(i==1)
    {

    }
    else
     {
        my_array[j] = my_array[i];
        j++;
     }

    }
     System.out.println("Original Array : "+Arrays.toString(my_array));   
    }
  }

Upvotes: 0

Alex Salauyou
Alex Salauyou

Reputation: 14348

If you need to remove one or multiple elements from array without converting it to List nor creating additional array, you may do it in O(n) not dependent on count of items to remove.

Here, a is initial array, int... r are distinct ordered indices (positions) of elements to remove:

public int removeItems(Object[] a, int... r) {
    int shift = 0;                             
    for (int i = 0; i < a.length; i++) {       
        if (shift < r.length && i == r[shift])  // i-th item needs to be removed
            shift++;                            // increment `shift`
        else 
            a[i - shift] = a[i];                // move i-th item `shift` positions left
    }
    for (int i = a.length - shift; i < a.length; i++)
        a[i] = null;                            // replace remaining items by nulls

    return a.length - shift;                    // return new "length"
}

Small testing:

Character[] words = {'c','d','f','h','j'};
removeItems(words, 1);
System.out.println(Arrays.asList(words));       // [c, f, h, j, null]

Upvotes: 1

lenhuy2106
lenhuy2106

Reputation: 313

If you don't want to use ArrayList, arraycopy is an alternative:

    System.arraycopy(words, 0, result, 0, i);
    System.arraycopy(words, i+1, result, i, result.length-i);

where i is your index to delete.

Hope I can help.

EDIT: Of course you should initially define the correct array lengths:

char[] result = new char[words.length-1];

Upvotes: 1

Fjotten
Fjotten

Reputation: 357

Assuming you do not want your array to contain null values, then you would have to make a method that does it. Something like this should suffice:

public char[] remove(int index, char[] arr) {
    char[] newArr = new char[arr.length - 1];
    if(index < 0 || index > arr.length) {
        return arr;
    }
    int j = 0;
    for(int i = 0; i < arr.length; i++) {
        if(i == index) {
            i++;
        }
        newArr[j++] = arr[i];
    }

    return newArr;
}

Then just replace the old array with the result of remove().

Upvotes: 1

Opalium
Opalium

Reputation: 141

You can't remove an element from the array and "reduce" the array size. Once you have created an array, it's length is fixed.

You could change the value to something that has no meaning or is considered "empty", but you can't remove it.
Another option is to use a list, such as an ArrayList. It has a "remove" method that allows you to actually remove the element from it.

Upvotes: 0

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