I want to sort an array with numbers in natural order, so numbers with a bigger value come after smaller ones like this:
php > $numbers = array('10 Apple', '2 Grapes', '3 Apples', '3.2 Apples', '3.1 Apples', '3.3 Apples', '3.10 Apples', '3.11 Apples', 'Lots of Apples'); php > natsort($numbers);
This is what I get as result, which is not the result I need, decimals are not threated correctly.
php > print_r($numbers); Array ( [1] => 2 Grapes [2] => 3 Apples [4] => 3.1 Apples [3] => 3.2 Apples [5] => 3.3 Apples [6] => 3.10 Apples [7] => 3.11 Apples [0] => 10 Apple [8] => Lots of Apples )
There is already a similar question Array Sorting in php for decimal values but no fitting answer was found there.
The expected output for a property sorting would be
Array ( [1] => 2 Grapes [2] => 3 Apples [4] => 3.1 Apples [6] => 3.10 Apples [7] => 3.11 Apples [3] => 3.2 Apples [5] => 3.3 Apples [0] => 10 Apple [8] => Lots of Apples )
So I would kind of expect natsort()
do to exactly that, but it looks like it is buggy and I have to implement a similar logic by my self? Is that correct?
One solution I am thinking of is to reformat the numbers somehow to fixed precision and hope that natsort()
works then, but I am wondering if there are easier solutions or PHP-builtin ones.
I tried https://github.com/awssat/numbered-string-order which is very interesting but also does not support decimals.
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Answer
I’m not 100% sure of your specification so please test this, but strnatcmp
seems like it can be used to run a natsort
variant in usort
. If both strings passed to the comparator start with float numbers, then cast them to floats and use the spaceship, otherwise, default to strnatcmp
.
<?php $numbers = ['10 Apple', '2 Grapes', '3 Apples', '3.2 Apples', '3.1 Apples', '3.3 Apples', '3.10 Apples', '3.11 Apples', 'Lots of Apples']; usort($numbers, function ($a, $b) { if (preg_match("~^d*.d+b~", $a, $m)) { $aa = (float)$m[0]; if (preg_match("~^d*.d+b~", $b, $m)) { $bb = (float)$m[0]; return $aa <=> $bb; } } return strnatcmp($a, $b); }); print_r($numbers);