How to modify the key name of an array in php

PHP, as a high-level programming language, has rich data types and operation methods. Array is one of the very basic and commonly used data types in PHP. It can store multiple values ​​and access these values ​​using keys. In practical applications, we often need to modify the key names of arrays to meet different business needs. This article will introduce several common methods of modifying key names in PHP arrays.

1. Use the array_combine() function

The array_combine() function can merge two arrays into one array at the same index position. If one of the arrays is used as the key of the new array, then the other array becomes the value of the new array. Through this function, we can quickly modify the key name of the array. For example:

<?php
$old_array = ["name" => "Lucy", "age" => 18];
$new_keys = ["name" => "username", "age" => "userage"];
$new_array = array_combine($new_keys, $old_array);
var_dump($new_array);
?>

The output result is as follows:

array(2) {
  ["username"]=>
  string(4) "Lucy"
  ["userage"]=>
  int(18)
}

You can see that the key names "name" and "age" in the original array have been modified to "username" and "userage".

2. Use the array_flip() and array_combine() functions

Use the array_flip() function to interchange the key names and key values ​​in the array, so that the original The key name becomes the key value, and then the array_combine() function is used to recombine the new key value and the old value into a new array. For example:

<?php
$old_array = ["name" => "Lucy", "age" => 18];
$old_keys = array_keys($old_array);
$new_keys = ["username", "userage"];
$flip_array = array_flip($old_array);
$new_array = array_combine($new_keys, $flip_array);
$new_array = array_flip($new_array);
$new_array = array_combine($new_keys, $old_array);
var_dump($new_array);
?>

The output result is as follows:

array(2) {
  ["username"]=>
  string(4) "Lucy"
  ["userage"]=>
  int(18)
}

You can see that the key names "name" and "age" in the original array have been modified to "username" and "userage".

3. Use foreach loop and unset() function

Use foreach loop and unset() function to traverse the array and change the key names to new names one by one. For example:

<?php
$old_array = ["name" => "Lucy", "age" => 18];
$new_keys = ["username" => "name", "userage" => "age"];
$new_array = [];
foreach ($old_array as $key => $value) {
  if (isset($new_keys[$key])) {
    $new_array[$new_keys[$key]] = $value;
    unset($new_keys[$key]);
  } else {
    $new_array[$key] = $value;
  }
}
var_dump($new_array);
?>

The output result is as follows:

array(2) {
  ["username"]=>
  string(4) "Lucy"
  ["userage"]=>
  int(18)
}

You can see that the key names "name" and "age" in the original array have been modified to "username" and "userage".

Summary:

The above three methods can realize the function of modifying key names in PHP arrays, and have certain applicability and efficiency. By mastering these methods, we can operate and use arrays more flexibly to meet different business needs. At the same time, in actual development, we should continue to learn in depth PHP's data types and operating methods, and continuously improve our programming level and capabilities.

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