How to sort an array based on a specific key-value pair using PHP, preserving the original key names?

Use the PHP uasort function and provide a comparison function to sort the array according to the specific key values ​​in the array while retaining the original key names. The specific steps are as follows: define a comparison function that accepts two key-value pairs as parameters and returns an integer; call the uasort function and pass in the array to be sorted and the comparison function; the sorted array will retain the original key names.

#How to use PHP to sort according to a specific key-value pair in an array, retaining the original key name?

In PHP, use the uasort function to sort according to a specific key-value pair in the array while retaining the original key name. Here is its syntax:

uasort(array $array, callable $value_compare_func)

Where:

• array The array to sort
• value_compare_func A comparison Function, which will be used to compare two key-value pairs in the array

The comparison function should accept two parameters (the key-value pairs of the two elements in the array) and return an integer:

• -1 If the first key-value pair should be sorted before the second key-value pair
• 0 If both key-value pairs For equality
• 1 If the first key-value pair should be ranked after the second key-value pair

Practical case

Suppose we have an array named $data which contains student information and their grades:

$data = [
    'John Doe' => 85,
    'Jane Smith' => 90,
    'Bob Jones' => 75
];

We can use the following code to sort the array based on grades, While retaining the original key names:

uasort($data, function($a, $b) {
    return $a - $b;
});

The sorted array will look like this:

print_r($data);
// 输出：
// Array
// (
//     [Jane Smith] => 90
//     [John Doe] => 85
//     [Bob Jones] => 75
// )

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