Sort array by value of a specific key [duplicate] - php

Question

This question already has answers here:
How can I sort arrays and data in PHP?
(14 answers)
Closed 7 years ago.
I've got an array as such:
$currentTerm = array(
'name' => $term->name,
'weight' => $term->weight
);
I'd like to sort the entire array by the weight key. I can't figure out how to accomplish this. Any thoughts or should I write a custom function for this?
P.S Some weights can be the same; so storing them as a key isn't an option. And it's multidimensional with a children key which is filled recursively the same way as above.

Answer 1

You can create a custom sorting method usort().
It would work similarly to this:
usort($array, function($a,$b) {
if($a->weight === $b->weight) return 0;
return ($a->weight < $b->weight) ? -1 : 1;
});
If people from the PHP7 future come here, they can just use this (spaceships!):
usort($array, function($a,$b) {
return $a->weight <=> $b->weight;
});
A full (and cumbersome) example for pre-PHP7 would be:
<?php
class Obj {
public $name;
public $weight;
function __construct($name,$weight) {
$this->name = $name;
$this->weight = $weight;
}
}
$array = array(
new Obj("A",3),
new Obj("B",10),
new Obj("C",8),
);
usort($array, function($a,$b) {
if($a->weight == $b->weight) return 0;
return ($a->weight < $b->weight) ? -1 : 1;
});
print_r($array);
?>

Answer 2

Take a look at array_multisort()
$weight = array();
foreach ($currentTerm as $key => $row)
{
$weight[$key] = $row['weight'];
}
then
array_multisort($weight, SORT_ASC, $currentTerm);
or
array_multisort($weight, SORT_DESC, $currentTerm);

Answer 3

You can try this code:
//define a comparison function
function cmp($a, $b) {
if ($a['status'] == $b['status']) {
return 0;
}
return ($a['status'] < $b['status']) ? -1 : 1;
}
usort($array, "cmp");