Sorting multidimentional array by the value in PHP

Question

Here I have a multidimentional array looks like this:

Array
(
    [1] => Array
        (
            [0] => 100
            [1] => a
        )

    [2] => Array
        (
            [0] => 1000
            [1] => b
        )

    [3] => Array
        (
            [0] => 50
            [1] => c
        )

    [4] => Array
        (
            [0] => 500
            [1] => d
        )

    [5] => Array
        (
            [0] => 1500
            [1] => e
        )

)

All I wanna do is sorting the array based on the [0] value, so it will be look like this:

Array
(
    [1] => Array
        (
            [0] => 1500
            [1] => e
        )

    [2] => Array
        (
            [0] => 1000
            [1] => b
        )

    [3] => Array
        (
            [0] => 500
            [1] => d
        )

    [4] => Array
        (
            [0] => 100
            [1] => a
        )

    [5] => Array
        (
            [0] => 50
            [1] => c
        )

)

Do you have any suggestion what I'm suppose to do? Thanks in advance

Answer 1

Easiest is to use a user defined function for sorting:

<?php
$values = [
    1 => [100, 'a'],
    2 => [1000, 'b'],
    3 => [50, 'c'],
    4 => [500, 'd'],
    5 => [1500, 'e']
];

usort($values, function($a, $b){
    return $a[0] < $b[0];
});

var_dump($values);

The output obviously is:

array(5) {
  [0] =>
  array(2) {
    [0] =>
    int(1500)
    [1] =>
    string(1) "e"
  }
  [1] =>
  array(2) {
    [0] =>
    int(1000)
    [1] =>
    string(1) "b"
  }
  [2] =>
  array(2) {
    [0] =>
    int(500)
    [1] =>
    string(1) "d"
  }
  [3] =>
  array(2) {
    [0] =>
    int(100)
    [1] =>
    string(1) "a"
  }
  [4] =>
  array(2) {
    [0] =>
    int(50)
    [1] =>
    string(1) "c"
  }
}