How to Sort Arrays in PHP

Handling sorted data is always easier to extract specific information, otherwise you have to iterate through each element of the array one by one.

For example, suppose you store the grades of different students in an array or table. If the data are not sorted by the grades obtained, you must check the grades of each student in the class to determine who gets the highest and lowest scores. If the table has been sorted from low to high by grades, you can know the lowest score by simply checking the first student’s grades.

This article will introduce the following PHP array sorting methods:

• Sort array by value

• Sort associative array

• Sort array elements by value using user-defined functions

• Key sorting array

• Sorting PHP multi-dimensional array

• Sorting with user-defined functions

• Multiple-column sort

Sorting makes it very easy and efficient for many tasks that require access to or obtaining a specific dataset. In this tutorial, we will learn how to sort arrays of different types using built-in PHP functions.

Sort array by value

In PHP, sorting arrays by element values ​​is very easy. You can choose to keep or discard key-value associations, or you can define your own functions to decide how to sort elements. I'll show you how to do it in this section of this tutorial.

You can use the array_multisort() function, which can sort multidimensional arrays based on multiple columns or multidimensional values. You just need to create an array containing the key values ​​you want to use for sorting. After that, just pass the sort flag.

The following example should give you a clear understanding:

$players = [
    [
        'name' => 'Adam',
        'score' => 70,
        'health' => 80
    ],
    [
        'name' => 'Joey',
        'score' => 60,
        'health' => 90
    ],
    [
        'name' => 'Monty',
        'score' => 70,
        'health' => 45
    ],
    [
        'name' => 'Andrew',
        'score' => 90,
        'health' => 80
    ],
    [
        'name' => 'Sally',
        'score' => 60,
        'health' => 85
    ],
    [
        'name' => 'Amanda',
        'score' => 98,
        'health' => 50
    ],
    [
        'name' => 'James',
        'score' => 50,
        'health' => 50
    ]
];

$p_score = array_column($players, 'score');
$p_health = array_column($players, 'health');

array_multisort($p_score, SORT_DESC, $p_health, SORT_ASC, $players);

We have a multi-dimensional array that stores the player's name, score and health. We use the $p_score and array_multisort() functions. This will have an impact on the final result. The $p_score we pass will be sorted in descending order. This will put Amanda on the top because she has the highest score. Now the elements in the $players array will also be rearranged so that Amanda's health is at the top in $players.

In other words, the $p_score arrays are arranged in descending order. The values ​​in other arrays will then be rearranged to match that order as well. Therefore, the order will be Amanda, Andrew, Adam, Monty and so on.

Once it goes through the entire $p_health array. You will notice that Adam and Monty have the same scores. Therefore, their final position will be determined by their health, which must be sorted in ascending order. Monty's health is lower than Adam, so he will be ahead of Adam. The order of players will now become Amanda, Andrew, Monty, Adam and so on.

All other values ​​conflicts are resolved in a similar way. Here is the final result you will get after sorting the array:

$players = [
    [
        'name' => 'Adam',
        'score' => 70,
        'health' => 80
    ],
    [
        'name' => 'Joey',
        'score' => 60,
        'health' => 90
    ],
    [
        'name' => 'Monty',
        'score' => 70,
        'health' => 45
    ],
    [
        'name' => 'Andrew',
        'score' => 90,
        'health' => 80
    ],
    [
        'name' => 'Sally',
        'score' => 60,
        'health' => 85
    ],
    [
        'name' => 'Amanda',
        'score' => 98,
        'health' => 50
    ],
    [
        'name' => 'James',
        'score' => 50,
        'health' => 50
    ]
];

$p_score = array_column($players, 'score');
$p_health = array_column($players, 'health');

array_multisort($p_score, SORT_DESC, $p_health, SORT_ASC, $players);

may be obvious now, but I still want to point out that sort() is calling a separate array. Here is an example:

print_r($players);
/*
Array
(
    [0] => Array
        (
            [name] => Amanda
            [score] => 98
            [health] => 50
        )

    [1] => Array
        (
            [name] => Andrew
            [score] => 90
            [health] => 80
        )

    [2] => Array
        (
            [name] => Monty
            [score] => 70
            [health] => 45
        )

    [3] => Array
        (
            [name] => Adam
            [score] => 70
            [health] => 80
        )

    [4] => Array
        (
            [name] => Sally
            [score] => 60
            [health] => 85
        )

    [5] => Array
        (
            [name] => Joey
            [score] => 60
            [health] => 90
        )

    [6] => Array
        (
            [name] => James
            [score] => 50
            [health] => 50
        )

)
*/

If your purpose is to sort the two arrays in ascending order, then use sort() for these two arrays separately.

Summary

In this tutorial, I showed you some different functions in PHP that can be used to sort arrays by keys or values. We also learned how to sort arrays by key or value using our own custom sorting criteria and uksort() and uasort() functions. The last section discusses how to sort all values ​​in a multidimensional array using only specific fields.

I hope you have learned something new from this tutorial. If you have any questions or suggestions, please let me know in the comments. The best way to learn is to try creating your own examples, using these functions to sort the arrays.

This article has been updated and contains contributions from Monty Shokeen. Monty is a full stack developer who also loves writing tutorials and learning new JavaScript libraries.

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