How to pick a random value from an array which is different from a specified value?

Question

I'm trying to make a random question feature of Question2Answer CMS. I would like to pick a random value from an array, but this value needs to be different from a specified value.

$current = '1138';
$randomarray = array("1", "3", "12", "50", "563", "889" ... "1140", "2700", "5290");

I would to sort out a random value from $randomarray, but there is still a chance that value can be 1138 (or programmatically $current). I want to rule out 1138. The random value must be different from 1138.

So, how can I do that?

Answer 1

If you need to preserve the original array you can use the function array_diff() to create a copy with the value of $current removed:

$temparray = array_diff($randomarray, [$current]);

If you don't need to preserve the original array use the function unset() to remove the value of $current:

unset($randomarray[$current]);

Note that array_diff() returns the result of the operation as a new array, so you must assign it to a variable, whereas unset() modifies the array in-place.

Either way, you can then pick a random index with the function array_rand() and use that index to get the value:

$i = array_rand($array);
echo $array[$i];

Replace $array with the correct array variable (either $temparray or $randomarray).