PHP multidimensional array search by value

Question

I have an array where I want to search the uid and get the key of the array.

Examples

Assume we have the following 2-dimensional array:

<

Answer 1

for( $i =0; $i < sizeof($allUsers); $i++)
    {   
    $NEEDLE1='firstname';
    $NEEDLE2='emailAddress';
    $sterm='Tofind';
     if(isset($allUsers[$i][$NEEDLE1]) && isset($allUsers[$i][$NEEDLE2])
        {
            $Fname= $allUsers[$i][$NEEDLE1];
            $Lname= $allUsers[$i][$NEEDLE2];

            $pos1 = stripos($Fname, $sterm);
            $pos2=stripos($Lname, $sterm);//not case sensitive 

            if($pos1 !== false ||$pos2 !== false)
            {$resultsMatched[] =$allUsers[$i];}
            else
            {   continue;}              
        }

}
Print_r($resultsMatched); //will give array for matched values even partially matched

With help of above code one can find any(partially matched) data from any column in 2D array so user id can be found as required in question.