Finding the minimum value's key in an associative array

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In PHP, say that you have an associative array like this:

$pets = array(
    "cats" => 1,
    "dogs" => 2,
    "fish" => 3
);

How would I find the key with the lowest value? Here, I'd be looking for cats.

Is there some built in PHP function that I've missed which does this? It would also be great if there was a solution that accounted for several values being identical, as below:

$pets = array(
    "cats" => 1,
    "dogs" => 1,
    "fish" => 2
);

Above, I wouldn't mind if it just output either; cats or dogs.

Thanks in advance.

6 Answers

Another approach for retrieving a single string is by using a desirable sorting method and retrieving the first key directly by using key() on the sorted array. In this instance the key with the lowest value is desired, asort will sort from lowest to highest values and reset the internal pointer. To retrieve the reverse (highest to lowest) use arsort.

Example: https://3v4l.org/5ijPh

$pets = array(
   "dogs" => 2,
   "cats" => 1,
   "fish" => 3
);
asort($pets);
var_dump(key($pets));
//string(4) "cats"
$pets = array(
   "dogs" => 1,
   "cats" => 1,
   "fish" => 3
);
asort($pets);
var_dump(key($pets));
//string(4) "dogs"

Take note that all of the PHP array sorting methods will alter the array by-reference. To prevent altering the original array, create a copy of the array or use an Iterator.

$petsSorted = $pets;
asort($petsSorted);
key($petsSorted);
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