Removing Array Element and Re-Indexing in PHP

In order to remove an element from an array, we can use unset() function which removes the element from an array, and then use array_values() function which indexes the array numerically automatically.

Function Used

unset():

This function unsets a given variable.

Syntax:

void unset ( mixed $var [, mixed $... ] )

array_values():

This function returns all the values from the array and indexes the array numerically.

Syntax:

array array_values ( array $array )

Example 1: We can also use array_splice() function which removes a portion of the array and replaces it with something else.

<?php 
$arr1 = array(

    'geeks', // [0]
    'for', // [1]
    'geeks' // [2]

);

// remove item at index 1 which is 'for'
unset($arr1[1]); 

// Print modified array
var_dump($arr1);

// Re-index the array elements
$arr2 = array_values($arr1);

// Print re-indexed array
var_dump($arr2);
?>

array(2) {
  [0]=>
  string(5) "geeks"
  [2]=>
  string(5) "geeks"
}
array(2) {
  [0]=>
  string(5) "geeks"
  [1]=>
  string(5) "geeks"
}

Example 2:

<?php 
$arr1 = array(
    'geeks', // [0]
    'for', // [1]
    'geeks' // [2]
);

// remove item at index 1 which is 'for'
array_splice($arr1, 1, 1); 

// Print modified array
var_dump($arr1);
?>

array(2) {
  [0]=>
  string(5) "geeks"
  [1]=>
  string(5) "geeks"
}

Using array_filter() with a Callback Function

Using `array_filter()` with a callback function allows you to remove specific elements from an array by filtering out elements based on a condition. The `ARRAY_FILTER_USE_KEY` flag enables filtering by key. The resulting array is then re-indexed with `array_values()`.

Example:

<?php
$array = ['apple', 'banana', 'cherry'];
$indexToRemove = 1; // Remove 'banana'

// Filter out the element at the specified index
$array = array_filter($array, function($key) use ($indexToRemove) {
    return $key != $indexToRemove;
}, ARRAY_FILTER_USE_KEY);

// Re-index the array
$array = array_values($array);

print_r($array);
?>

Array
(
    [0] => apple
    [1] => cherry
)

PHP is a server-side scripting language designed specifically for web development. You can learn PHP from the ground up by following this PHP Tutorial and PHP Examples.