array_search recursive function php

Question

I have this function which is supposed to generate random numbers and make sure they are not in the exceptions array, but I have this corner case:

It does not execute the while condition:

Exceptions Array
(
    [0] => 84
    [1] => 94
    [2] => 46

)

print_r ouput : number generated is 46 we have a match number im going to return is 84

so it does the first check correctly but not the recursive check, so it returns to me a duplicate value 84, is my while condition wrong?

function randWithout($from, $to, array $exceptions) {
    //sort($exceptions); // lets us use break; in the foreach reliably
    echo '<pre>';
    print_r($exceptions);
    echo '</pre>';
    $number = mt_rand($from, $to); 
    print_r('number generated is' . $number);
    if(array_search($number,$exceptions) != FALSE) 
    {
        echo 'we have a match';
        do {

            $number = mt_rand($from, $to);

        } while(array_search($number,$exceptions) === FALSE);
    }
    print_r('number im going to return is'. $number);
    return $number;
}

Maybe I'm just blind, but I don't see any recursion in the above. Could you point it out? — Daedalus
– Daedalus, Commented Jan 27, 2014 at 23:06
while(array_search($number,$exceptions) === FALSE) but 'im thinking i just need a return $number inside that if loop — Edward
– Edward, Commented Jan 27, 2014 at 23:07
Recursion is when a function calls itself. That's not happening above. — Daedalus
– Daedalus, Commented Jan 27, 2014 at 23:08
whats with the print_r ? the code above does not work as is — user557846
– user557846, Commented Jan 27, 2014 at 23:09
theres nothing recursive. its an iteration. if is a statement not a loop. — sjkm
– sjkm, Commented Jan 27, 2014 at 23:09

Reza S · Accepted Answer · 2014-01-27 23:42:16Z

1

Ok here's what you should change it to:

$ex = [12,18,15];

for($i=0; $i<20;$i++) {
    print randWithout(10,20,$ex) . PHP_EOL;
}

function randWithout($from, $to, array $exceptions) {
    do {
        $number = mt_rand($from, $to);
    } while(in_array($number,$exceptions));

    return $number;
}

Just tested it and it works.

edited Jan 27, 2014 at 23:42

answered Jan 27, 2014 at 23:08

Reza S

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Edward Over a year ago

array_search returns the key for needle if it is found in the array, FALSE otherwise. So it should work fine, I tried in_array() same problem.

Edward · Accepted Answer · 2014-01-27 23:39:09Z

0

changed to:

if(in_array($number,$exceptions) != FALSE) 
    {
        echo 'we have a match';
        do {

            $number = mt_rand($from, $to);

        } while(in_array($number,$exceptions));
    }

Removed the == FALSE clause from in_array, as it returns true if needle is found.

answered Jan 27, 2014 at 23:39

Edward

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