Performance: is_numeric() and is_string() in a foreach loop

Question

I have a bunch of arrays in an array ex.

$array =
         array(
            array(/../),
            array(/../),
            array(/../),
            //upto 100-200 arrays
         );

After that, I will use foreach to echo all of them. There is some checking here whether the $key is is_numeric() or is_string(), for example:

array(
   'the_key_here_is_numeric',
   'string' => 'the key is string'
);

So I have a foreach like this:

foreach($array as $arr => $arrays) {
   foreach($arrays as $key => $value) {
      if(is_numeric($key)) {
         /.../
      }
      if(is_string($key)) {
         /../
      }
   }
   echo /../;
}

When I tested this using KCacheGrind, obviously the is_string() and is_numeric() will be used multiple times, my question is, will this affect the performance? If so, is there a better way to do this?

Answer 1

Just use else. Then condition will be check only once

Not

if(is_numeric($key)) {
         /.../
      }
      if(is_string($key)) {
         /../
      }

But

  if(is_string($key)) {
     /../
  } else {
     /.../
  }