How to modify the key name in an array in PHP

PHP is a very powerful programming language, and arrays are one of the most commonly used data types in PHP. When processing data in an array, sometimes we need to modify the key names in the array. So, how to modify the key name in the array in PHP? This article will introduce this issue to you in detail.

1. Modify all array key names

In PHP, we can use the array_combine() function to combine the keys of one array and the values ​​of another array into a new array. For example:

$arr1 = array('a', 'b', 'c');
$arr2 = array('apple', 'banana', 'orange');
$new_arr = array_combine($arr1, $arr2);
print_r($new_arr);

The output result is as follows:

Array
(
    [a] => apple
    [b] => banana
    [c] => orange
)

As you can see, through the array_combine() function, we merge the keys of array $arr1 and the value of array $arr2 into a new array $new_arr. At this time, the key names of $new_arr have all been modified.

2. Modify the key name of the specified element

If we only need to modify the key name of an element in the array, we can use the unset() function to delete the element, and then use The new key adds the element back to the array. For example:

$arr = array('a' => 'apple', 'b' => 'banana', 'c' => 'orange');
unset($arr['b']);
$arr['new_key'] = 'banana';
print_r($arr);

The output result is as follows:

Array
(
    [a] => apple
    [c] => orange
    [new_key] => banana
)

As you can see, we use the unset() function to delete the 'b' element in the array, and then use the new key name 'new_key' Add the element back to the array, thereby modifying the key name.

3. Use the array_splice() function to modify the key name

In addition to using the unset() function, we can also use the array_splice() function to modify the key name of the specified element in the array. This function can delete an element from the array and return the deleted element. Then, we add the element back to the array with a new key. For example:

$arr = array('a' => 'apple', 'b' => 'banana', 'c' => 'orange');
$old = array_splice($arr, 1, 1);
$arr['new_key'] = $old[0];
print_r($arr);

The output is as follows:

Array
(
    [a] => apple
    [new_key] => banana
    [c] => orange
)

As you can see, we use the array_splice() function to delete the 'b' element in the array and save it in the variable $old. Then, we add the element back to the array with the new key name, thereby achieving the purpose of modifying the key name.

4. Use the array_replace() function to modify the key name

Finally, we can also use the array_replace() function to modify the key name of the specified element in the array. This function can merge one or more arrays into one array and use the subsequent array to overwrite elements with the same key name. For example:

$arr = array('a' => 'apple', 'b' => 'banana', 'c' => 'orange');
$new_arr = array_replace($arr, array('b' => 'grapefruit'));
print_r($new_arr);

The output result is as follows:

Array
(
    [a] => apple
    [b] => grapefruit
    [c] => orange
)

As you can see, we use the array_replace() function to change the value of the element with the key name 'b' from 'banana' to 'grapefruit' .

Summary

This article introduces four methods of modifying array key names in PHP, including modifying all array key names, modifying the key names of specified elements, and using the array_splice() function. Key name and use the array_replace() function to modify the key name. Different methods have their own advantages and disadvantages, and you can choose the appropriate method according to actual needs. I hope that through the introduction of this article, everyone can master the skills of how to modify the array key name in PHP.

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