Sorting method of php two-dimensional array
This article mainly talks about "the sorting method of php two-dimensional array". Interested friends may wish to have a look. The method introduced in this paper is simple, fast and practical. Now let the editor to take you to learn "the sorting method of php two-dimensional array"!
The copy code is as follows:
$users = array (
Array ('name' = >' tom', 'age' = > 20)
, array ('name' = >' anny', 'age' = > 18)
, array ('name' = >' jack', 'age' = > 22)
);
I want to be able to sort by age from small to big. The author sorted out two methods and shared them with you.
1. Use array_multisort
Using this method, it is more troublesome to extract the age and store it in an one-dimensional array, and then sort it in ascending order of age. The specific code is as follows:
The copy code is as follows:
$ages = array ()
Foreach ($users as $user) {
$ages [] = $user ['age']
}
Array_multisort ($ages, SORT_ASC, $users)
After execution, $users is the sorted array, which can be printed out. If you need to sort by age ascending order, and then by name ascending order, the method is the same as above, it is to extract one more name array, and the final sorting method is called like this:
The copy code is as follows:
Array_multisort ($ages, SORT_ASC, $names, SORT_ASC, $users)
2. Use usort
The biggest advantage of using this method is that you can customize some of the more complex sorting methods. For example, sort in descending order by the length of the name:
The copy code is as follows:
Usort ($users, function ($a, $b) {
$al = strlen ($a ['name'])
$bl = strlen ($b ['name'])
If ($al = = $bl)
Return 0
Return ($al > $bl)?-1: 1
});
Anonymous functions are used here, which can be extracted separately if necessary. Where $a, $b can be understood as the elements under the $users array, you can directly index the name value, calculate the length, and then compare the length.
The author prefers the second method because there are fewer steps to extract the sorted content into an one-dimensional array, and the sorting method is more flexible.
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