How to delete elements and indexes in an array in php

In PHP, if you want to delete elements and indexes in an array, you can use the following method:

1. unset function

You can use PHP’s built-in unset function to Delete array elements and indices. The function takes one or more arguments, each of which is the name of a variable or array element to be deleted.

For example, the following code deletes the first element of the array $numbers:

$numbers = array(1, 2, 3, 4, 5);
unset($numbers[0]); //删除第一个元素
print_r($numbers); //输出：Array ( [1] => 2 [2] => 3 [3] => 4 [4] => 5 )

Here, the unset function is used to delete the first element of the array $numbers, and the print_r function is used to display the deletion. array.

2. array_splice function

You can use the array_splice function to remove array elements and retain the index. This function takes 3 parameters: array variable, starting index, and number of elements to delete.

For example, the following code deletes the second and third elements of the array $numbers:

$numbers = array(1, 2, 3, 4, 5);
array_splice($numbers, 1, 2); //从第二个元素开始删除两个元素
print_r($numbers); //输出：Array ( [0] => 1 [3] => 4 [4] => 5 )

Here the array_splice function is used to delete two elements starting from the second element of the array $numbers , and use the print_r function to display the deleted array.

3. array_filter function

You can use the array_filter function to delete array elements and indexes. This function takes two parameters: the array to process and the callback function.

For example, the following code deletes the even elements in the array $numbers:

$numbers = array(1, 2, 3, 4, 5);
$numbers = array_filter($numbers, function($value) {
    return $value % 2 != 0;
}); //删除偶数元素
print_r($numbers); //输出：Array ( [0] => 1 [2] => 3 [4] => 5 )

Here the array_filter function is used to delete the even elements in the array $numbers, and the print_r function is used to display the deleted array.

Summary

The above three methods can be used to delete elements and indexes in PHP arrays, and the usage scenarios of each method are different. By mastering these methods, you can better manage and manipulate your PHP arrays.

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