Question

function remove_values($arr){
    $_a = array();
    while(list($key,$val) = each($arr)){
        $_a[$val] = 1;
    }
    return array_keys($_a);
}

i can’t follow the above function well.i don’t know what’s the effect of $_a[$val] = 1; anyone can explain it to me thank you

Answer 1

Well all this does is to insert the value into the key of an array. Since all keys are unique in an array, you will remove all duplicates.

array_keys() simply gives back that array in it’s ordinary form.

Example:

$arr = array('red', 'green', 'red');

$arr = remove_values($arr);

gives

array( 'red' => 1,
       'green' => 1);

which results in

array('red', 'green');

since “red” can only be a keyvalue once.