in reply to
Diff between two arrays
How are you to determine that "burritoes" (sic) is a replacement for "tacos" ?? What are the rules that determine that, without also determining that "Do" is a replacement for "I"?
I'm sure you have an END RESULT in mind (ie. why are you trying to do this?), and you are currently trying to solve a problem that is getting in the way of your solution... if you can say what you are trying to achieve, likely you'll find there somebody has a better SOLUTION so that you won't have to solve this problem you are dealing with.