Sort Associative Arrays in PHP by a Specific Key

In PHP, you can sort an associative array by a specific key using the usort() function in combination with a custom comparison function. Here’s an example:

<?php
// Sample associative array
$students = array(
    array('name' => 'Alice', 'age' => 20, 'score' => 85),
    array('name' => 'Bob', 'age' => 21, 'score' => 72),
    array('name' => 'Charlie', 'age' => 19, 'score' => 90),
    array('name' => 'David', 'age' => 20, 'score' => 80)
);

// Define a custom comparison function based on the 'score' key
function compare_by_score($a, $b) {
    return $a['score'] < $b['score'] ? 1 : -1;
}

// Sort the array using the custom comparison function
usort($students, 'compare_by_score');

// Print the sorted array
print_r($students);
?>

In this example, we define a custom comparison function called compare_by_score() that compares two elements of the array based on their ‘score’ key. We then pass this function as the second argument to the usort() function, which sorts the $students array in descending order of score.

You can modify the custom comparison function to sort the array by a different key or in a different order.