How to change array index name in php

PHP is an open source server-side scripting language primarily used for web development. It uses a C-like syntax structure that can easily handle dynamic content and interact with various data representation formats such as HTML and XML. There are many kinds of arrays in PHP, which can be defined using lists, key-value pairs, and multidimensional arrays. When working with arrays, it is sometimes necessary to change the index name of the array to make it more meaningful and readable.

In PHP, you can use some built-in functions to change the array index name. Two of the commonly used functions are introduced below: array_change_key_case() and array_combine().

1. array_change_key_case()

array_change_key_case() function is used to change all the key names of the array to uppercase or lowercase. It can unify the naming style of the key names and improve the code. readability and maintainability. This function accepts a parameter, which means converting the key name to uppercase or lowercase. The parameter value is CASE_UPPER or CASE_LOWER, and the default is CASE_LOWER. The example is as follows:

$arr = array('name'=>'张三', 'age'=>20, 'gender'=>'男');
$newArr = array_change_key_case($arr, CASE_UPPER);
print_r($newArr);

The output result is:

Array
(
    [NAME] => 张三
    [AGE] => 20
    [GENDER] => 男
)

You can see that the key names in the original array are converted to uppercase and saved in the new array.

2. array_combine()

array_combine() function is used to merge two arrays into a new array, with one array as the key name of the new array and the other array as the value of the new array. This function accepts two parameters, the first parameter is the key array, and the second parameter is the value array. It should be noted that the two arrays must be of equal length. The example is as follows:

$keyArr = array('name', 'age', 'gender');
$valueArr = array('张三', 20, '男');
$newArr = array_combine($keyArr, $valueArr);
print_r($newArr);

The output result is:

Array
(
    [name] => 张三
    [age] => 20
    [gender] => 男
)

As you can see, the key name of the new array comes from the $keyArr array, and the value comes from the $valueArr array. This way you can merge arrays according to your needs.

To sum up, you can use the built-in functions array_change_key_case() and array_combine() in PHP to change the index name of the array. By using these functions, array operations can be made more flexible and convenient, and the readability and maintainability of the code can be improved.

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