CODEWITHSUNDEEP
phpassociative-array
Philip Morton
Philip Morton

Reputation: 131979

Finding the minimum value's key in an associative array

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.

Upvotes: 52

Views: 62049

Answers (6)

Will B.
Will B.

Reputation: 18426

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);

Upvotes: 1

lexx
lexx

Reputation: 141

Thats how i did it.

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

array_search(min($pets), $pets);

I hope that helps

Upvotes: 14

Rohit Suthar Mumbai
Rohit Suthar Mumbai

Reputation: 11

find the highest value 

print max(120, 7, 8, 50);

returns --> 120

$array = array(100, 7, 8, 50, 155, 78);
print max($array);

returns --> 155

find the lowest value 

print min(120, 7, 8, 50);

returns --> 7

$array = array(50, 7, 8, 101, 5, 78);
print min($array);

returns --> 5

Upvotes: -3

Jeff Ober
Jeff Ober

Reputation: 5027

$min_val = null;
$min_key = null;
foreach($pets as $pet => $val) {
  if ($val < $min_val) {
    $min_val = $min;
    $min_key = $key;
  }
}

You can also flip the array and sort it by key:

$flipped = array_flip($pets);
ksort($flipped);

Then the first key is the minimum, and its value is the key in the original array.

Upvotes: 2

Phill Pafford
Phill Pafford

Reputation: 85368

Might try looking into these:

Upvotes: 3

SilentGhost
SilentGhost

Reputation: 319881

array_keys is your friend:

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

P.S.: there is a dup here somewhere on SO (it had max instead of min, but I can distinctly remember it).

Upvotes: 121

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