CODEWITHSUNDEEP
phparrayssorting
Sam
Sam

Reputation: 57

sort array by use of GET variable.. no sorting

I have an array consisting of 4 fields.

 $retval[] = array(
      "name" => "$dir$entry/",
      "type" => filetype("$dir$entry"),
      "size" => 0,
      "lastmod" => filemtime("$dir$entry")
    );

I want to sort this array depending on a variable, which contains either 1 of the 4 field (eg: type, name etc)

$sortBy = $_GET['sortBy'];

This function should use the $sortBy variable:

function compare_field($a, $b){
return strnatcmp($a["'.$sortBy.'"], $b["'.$sortBy.'"]) 
}

And is called like this:

usort($retval, "compare_field");

But the construction doesn't work ..

Hope someone can point me in the right direction, being the obvious newby I am.

Upvotes: 1

Views: 53

Answers (1)

Elias Van Ootegem
Elias Van Ootegem

Reputation: 76413

First, you're sorting by a key that is actually: '..', not the value of $sortBy. You're trying to use a variables value as the key, to do that, you don't need to mess around with quotes, just write $arrayName[$keyVariable]. That's it.
Second is that compare_field had no access to the $sortBy variable. That variable is local to the scope where it was created, or it's a global variable. Either way, functions don't have access to it.

If you want the usort callback to have access to the $sortBy variable, the easiest way would be to use a closure (anonymous function) as callback:

usort($retval, function ($a, $b) use ($sortBy) {
    return strnatcmp($a[$sortBy], $b[$sortBy]);
});

Upvotes: 3

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