How to change array column name in php

PHP is a very commonly used server-side scripting language. In PHP, array is a very commonly used structure. It can store multiple data elements in a separate variable, making it easier for us to manage and operate data. However, in actual development, sometimes it is necessary to change the array specification to better meet actual needs.

Generally, we have already defined the column names of the array when we define it. For example:

$users = array(
    array('id'=>1,'name'=>'Tom','age'=>20),
    array('id'=>2,'name'=>'John','age'=>22),
    array('id'=>3,'name'=>'Mary','age'=>21),
);

The above code defines an array containing three array elements, each element has three columns: id, name and age. However, in actual development, we may need to change the listing to better meet actual needs. For example, we want to change the id to userId, the name to userName, and the age to userAge. How to do this? The answer is to use the array_map function in PHP.

First, we need to create a conversion function, which maps the old column names to the new column names. For example, we define the following conversion function:

function transformKeys($keys) {
    $newKeys = array();
    foreach ($keys as $key) {
        switch ($key) {
            case 'id':
                $newKeys[] = 'userId';
                break;
            case 'name':
                $newKeys[] = 'userName';
                break;
            case 'age':
                $newKeys[] = 'userAge';
                break;
            default:
                $newKeys[] = $key;
        }
    }
    return $newKeys;
}

This function receives an array as a parameter, traverses each element of the array, uses a switch statement to map the old column name to a new column name, and returns a new array.

Next, we use the array_map function to apply the conversion function to the original array. The code is as follows:

$users = array_map(function($user) {
    $keys = array_keys($user);
    $newKeys = transformKeys($keys);
    $values = array_values($user);
    $transformedValues = array_combine($newKeys, $values);
    return $transformedValues;
}, $users);

In the code, we first use the array_keys function to obtain the listing of the original array, Then call the conversion function transformKeys to map the old list to the new list. Next, we use the array_values ​​function again to obtain the values ​​of the original array, and then use the array_combine function to combine the new column names and the values ​​​​of the original array to form a new array.

Finally, we assign the array with changed column names to the $users variable, making it an array with changed column names.

Through the above operations, we can easily change the array column names in PHP to better meet actual needs. Of course, in practical applications, we also need to analyze specific situations and achieve the best code efficiency as much as possible while keeping the code concise and clear.

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