Comparing arrays to produce a key array in PHP

I have a problem that I'm sure is easy to solve with PHP's inbuilt functions or with one or two lines of code, but I cant seem to find a solution using my limi开发者_StackOverflow中文版ted experince.

I have a master array:

$master_array = ('location_1','location_2','location_3','location_4','location_5');

I get given an array:

$submitted_array = ('location_1','location_3');

And I need to compare both arrays to form an array such as this:

$locations = (0,2);

Where the numbers in the $locations array are the locations of the $submitted_array elements in the $master_array.

There must be a way of doing this without loops, surely.

$result = array_keys(array_intersect($master_array , $submitted_array));
print_r($result);

$locations = array_keys(array_intersect($master_array, $submitted_array));