PHP function - screening array sanity check

Question

I'm writing a function to loop through an array until a match is found based on another array. However the value is returning null.

My example:

$i = 1;
$tmp = ['fff'=>111,'aaa'=>100,'ddd'=>99,'ccc'=>87,'eee'=>45,'bbb'=>3,'ggg'=>1];
$prg = ['bbb','ccc'];
function doFilter($tmp,$prg,$i) {                   
    $second = array_slice($tmp, $i, 1);
    $snd = key($second);
    if (!in_array(strtolower($snd),$prg)) {
        $i++;
        doFilter($tmp,$prg,$i);
    } else {
        // echo ccc
        echo $snd;
        return $snd;
    }                   
}
$snd = doFilter($tmp,$prg,$i);
// echo NULL
echo $snd;

Any thoughts why the value within the function is not being returned to populate the variable as a response from the function?

Why are you doing this recursively? Also, are you just trying to see if 1 $prg is in $tmp or you want to see all $prg that are in $tmp? — AbraCadaver
– AbraCadaver, Commented Apr 20, 2017 at 19:58
You don't return the value from the inner recursive calls.You probably want return doFilter($tmp,$prg,$i); — jh1711
– jh1711, Commented Apr 20, 2017 at 20:01
fantastic, thanks! yes, was not returning the recursive loop. — Cole Henley
– Cole Henley, Commented Apr 20, 2017 at 20:04
but yes, there is probably an easier way to do it, although comparing keys in one array to values in the other. — Cole Henley
– Cole Henley, Commented Apr 20, 2017 at 20:04

mickmackusa · Accepted Answer · 2017-04-20 23:00:39Z

1

This can all be efficiently done with array_intersect() and array_keys().

Code (Demo):

$tmp = ['fff'=>111,'aaa'=>100,'ddd'=>99,'ccc'=>87,'eee'=>45,'bbb'=>3,'ggg'=>1];
$prg = ['bbb','ccc'];

echo "1st Key: ",(sizeof($result=array_intersect(array_keys($tmp),$prg))==0?"Not Found":current($result));
echo "\n\nResult Array: ";
var_export($result);

Output:

1st Key: ccc

Result Array: array (
  3 => 'ccc',
  5 => 'bbb',
)

Alternatively if you want to get the value of the first match:

var_export(current(array_intersect_key($tmp,array_flip($prg))));
// Will ouput: 87
// if no matches, will return FALSE

edited Apr 20, 2017 at 23:00

answered Apr 20, 2017 at 22:52

mickmackusa♦

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