How to dynamically modify the array length in php

In PHP, array is a very common data type. In some cases, we need to dynamically modify the length of the array while the program is running to meet different needs. This article will introduce how to dynamically modify the length of an array in PHP.

1. Use the array_pad() function

The array_pad() function is a very useful array function in PHP. It can extend an array to the specified length and use the specified Value populates the new element. The function prototype is as follows:

array_pad(array $array, int $size, mixed $value)

Among them, $array represents the array that needs to be expanded, $size represents the length of the new array, $ value represents the value to fill in the new array element.

The following is a sample code:

$arr = array('apple', 'banana', 'orange');
$new_arr = array_pad($arr, 6, 'grape');
print_r($new_arr);

Output result:

Array
(
    [0] => apple
    [1] => banana
    [2] => orange
    [3] => grape
    [4] => grape
    [5] => grape
)

2. Use array_push() and array_pop() functions

In PHP, we can add one or more elements to the end of an array using the array_push() function. The syntax of this function is as follows:

array_push(array &$array, mixed $value1, mixed $value2, ...)

Among them, $array represents the array to which elements need to be added, $value1 , $value2, etc. represent elements that need to be added.

Similarly, we can use the array_pop() function to remove the last element from the end of the array. The function prototype is as follows:

mixed array_pop(array &$array)

Among them, $array represents the array whose elements need to be deleted.

The following is a sample code:

$arr = array('apple', 'banana', 'orange');
array_push($arr, 'grape', 'pineapple');
array_pop($arr);
print_r($arr);

Output result:

Array
(
    [0] => apple
    [1] => banana
    [2] => orange
    [3] => grape
)

3. Use array_splice() function

array_splice() function It is a very powerful array function in PHP. It can insert, delete, and replace elements in the array, and it can also dynamically modify the length of the array. The function prototype is as follows:

array array_splice(array &$input, int $offset, int $length = count($input), mixed $replacement = [])

Among them, $input Represents the array that needs to be operated, $offset indicates the starting position of insertion or deletion, $length indicates the number of deleted elements, and $replacement indicates the inserted element.

The following is a sample code:

$arr = array('apple', 'banana', 'orange');
array_splice($arr, 1);
print_r($arr);
array_splice($arr, 0, 1, 'grape');
print_r($arr);
array_splice($arr, 2, 0, array('pear', 'pineapple', 'watermelon'));
print_r($arr);

Output result:

Array
(
    [0] => apple
)
Array
(
    [0] => grape
    [1] => orange
)
Array
(
    [0] => grape
    [1] => orange
    [2] => pear
    [3] => pineapple
    [4] => watermelon
)

In short, the above are several ways to dynamically modify the length of an array in PHP. According to actual needs, we can choose a method that suits us to operate the array.

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