The sorting problem of PHP multidimensional array

Arrays have very powerful features and flexibility and are widely used in PHP. PHP provides a number of sorting functions for one-dimensional arrays, such as sort (), Ksort (), and so on, using them to easily sort a one-dimensional array. But it cannot be used for two-dimensional array ordering, but we can use PHP provided by Usort (), Uasort (), Uksort () and other functions for two-dimensional sorting.

Use Usort () to sort one-dimensional arrays:

function My_sort ($a, $b) {if ($a = = $b) return 0;return ($a < $b)? -1:1;} $a =array (4,2,8,6); usort($a,"my_sort")

The Usort () function is sorted by a user-defined comparison function, but the keyword is not saved.
Uasort () will save the keyword.
Uksort () sorting will be based on keywords

Use Usort () to sort two-dimensional arrays:
$students = Array (
[' Name ' = ' Lili ', ' grade ' = ' 35 '),

2 = = Array (' name ' = ' Zhangsan ', ' grade ' = ' 95 '),

3 = = Array (' name ' = ' Wangwu ', ' grade ' = ' 88 ')

);

function Name_sort ($x, $y) {
return strcasecmp ($x [' name '], $y [' name ']);
}

function Grade_sort ($x, $y) {
return $x [' Grade '] < $y [' grade '];
}

Uasort ($students, ' name_sort ');

The sorting problem of PHP multidimensional array