How to sort an Array of Associative Arrays by Value of a Given Key in PHP ?

Each entry in the associative array is characterized by a unique key-value pair. An array can contain singular data types belonging to variables or other arrays as its elements. There are multiple ways to sort an array of associative arrays by the value of a specified key. 

Approach 1: Using the array_multisort() method

The array_multisort() method is used to return a sorted array. String keys will be maintained, but the numeric keys are re-indexed, and they start at 0 and increase by 1. This function can sort multiple arrays at once or a multidimensional array. 

Example: In this approach, initially an array of associative arrays is defined. Then, a new array is created in order to store the keys as the attribute of the main array upon which we wish to sort. The array_multisort() method is then applied to this created array and the desired sort type. In case two or more keys are the same, the values appear in the order of storage. 

Output:

Explanation: The main array is sorted based on names in ascending order. 

Approach 2: Using the usort() method

This method sorts the given array using a user-defined comparison function. The user-defined function should return an integer than 0 if the first argument is than the second argument. This method assigns new keys to the elements in the array. It just removes any existing keys that may have been assigned, rather than just simply reordering the keys.

Example:

Output: The DescSort() method sorts the marks in descending order.