I don't understand your filtering / display requirements; your example doesn't clarify the situation.

A friendly suggestion: please show us what you've written, and then point to the areas you're uncertain about. We'll be happy to answer your questions. But you seem to be saying you don't know how to open a file, how to read a recod from the file into an array, how to do a regex, how to write to an output file.

If you don't know how to do any of that, and won't ask your teacher for a tutor, we'd be doing you a disservice by writing your entire assignment for you.