How to filter an array by a condition

Question

I have an array like this:

array(\"a\" => 2, \"b\" => 4, \"c\" => 2, \"d\" => 5, \"e\" => 6, \"f\" => 2)

Now I want to fi

Answer 1

You can iterate on the copies of the keys to be able to use unset() in the loop:

foreach (array_keys($array) as $key) {
    if ($array[$key] != 2)  {
        unset($array[$key]);
    }
}

The advantage of this method is memory efficiency if your array contains big values - they are not duplicated.

EDIT I just noticed, that you actually only need the keys that have a value of 2 (you already know the value):

$keys = array();
foreach ($array as $key => $value) {
    if ($value == 2)  {
        $keys[] = $key;
    }
}