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phparraysmaxarray-push

Why does max(array_push()) not find max?

Up front, I would like to clarify that I am not looking for a workaround to find max--I already have the solution for accomplishing that goal. What I am curious about is why max(array_push()) doesn't work.

I have an array with many values in it, and want to find the max of specific values within that array. Existing array:

$array1 = array(2,6,1,'blue','desk chair');

The basic idea is to create a new array consisting of those specified values, and then find the max of that new array. I attempted to make this effort operate all on one line:

$max = max(array_push($array2, $array1[0], $array1[1], $array1[2]));
//this doesn't work at all, since $array2 doesn't already exist, as per the PHP manual

I changed to code to first create $array2, but didn't assign values at that time, just to see if the code works.

$array2 = array();
$max = max(array_push($array2, $array1[0], $array1[1], $array1[2]));
//$array2 is populated, but $max is not assigned

The obvious solution is to assign values to $array2 at creation and then use max() by itself. I'm just curious as to why max(array_push()) doesn't find max, since compounded functions normally operate from inside to outside.

Thank you.

Solution

  • max needs an array to work with but array_push returns an integer and actually uses the provided array by reference, you have to do :

    $array2 = array();
array_push($array2, $array1[0], $array1[1], $array1[2])
$max = max($array2);

    Alternatively do: 

    $array2 = array($array1[0], $array1[1], $array1[2]);
$max = max($array2);

    A 3rd option (though not the cleanest one):

    $array2 = array();
$max = max($array2 = array_merge($array2, [$array1[0], $array1[1], $array1[2]]));

    For reference, see: