Java Language Remove an element from an array


Java doesn't provide a direct method in java.util.Arrays to remove an element from an array. To perform it, you can either copy the original array to a new one without the element to remove or convert your array to another structure allowing the removal.

Using ArrayList

You can convert the array to a java.util.List, remove the element and convert the list back to an array as follows:

String[] array = new String[]{"foo", "bar", "baz"};

List<String> list = new ArrayList<>(Arrays.asList(array));

// Creates a new array with the same size as the list and copies the list
// elements to it.
array = list.toArray(new String[list.size()]);

System.out.println(Arrays.toString(array)); //[bar, baz]

Using System.arraycopy

System.arraycopy() can be used to make a copy of the original array and remove the element you want. Below an example:

int[] array = new int[] { 1, 2, 3, 4 }; // Original array.
int[] result = new int[array.length - 1]; // Array which will contain the result.
int index = 1; // Remove the value "2".

// Copy the elements at the left of the index.
System.arraycopy(array, 0, result, 0, index);
// Copy the elements at the right of the index.
System.arraycopy(array, index + 1, result, index, array.length - index - 1);

System.out.println(Arrays.toString(result)); //[1, 3, 4]

Using Apache Commons Lang

To easily remove an element, you can use the Apache Commons Lang library and especially the static method removeElement() of the class ArrayUtils. Below an example:

int[] array = new int[]{1,2,3,4};
array = ArrayUtils.removeElement(array, 2); //remove first occurrence of 2
System.out.println(Arrays.toString(array)); //[1, 3, 4]
Sorting arrays