$arr = asort($arr);
//some magic code goes here, $arr is not changed
$arr = array_unique($arr);
Should I use asort again to be sure $arr is asorted?
My tests show that no, I don't. But I'm not sure for 100% if array_unique actually removes the 2nd+ repeated elements.
You merely want to ensure that asort and array_unique use the same sort_flags.
By default:
So you can see that each will sort based on a different algorithm, which might mostly match up, but you want it to explicitly match up. Thus, the smart money is on making a decision like:
<?php
$input = array("a" => "green", "red", "b" => "green", "blue", "red");
asort($input,SORT_REGULAR);
print_r($input);
print "\n";
$result = array_unique($input,SORT_REGULAR);
print_r($result);
Resulting in:
Array
(
[1] => blue
[a] => green
[b] => green
[2] => red
[0] => red
)
Array
(
[1] => blue
[a] => green
[2] => red
)
Also note that if you merely run array_unique without the initial asort, you will get different results.
Finally note that asort supports two flags that array_unique does not support:
SORT_NATURAL - compare items as strings using "natural ordering"
like natsort() SORT_FLAG_CASE - can be combined (bitwise OR) with
SORT_STRING or SORT_NATURAL to sort strings case-insensitivelyIf you use either of these two in your asort then you would necessarily need to asort again after array_unique.
No you do not need to. array_unique will only remove elements, so the order will always be preserved.
If you do not modify the array after the 'asort()', the array will be ordered.
No, you shouldn't. The function array_unique preserves keys, so there is no need to sort it again.
