Soheil Moayedi Azarpour covers the basics of regular expressions and iOS:
If you have been eager to know more about using regular expressions in iOS, look no further than this tutorial — no previous experience required!
By the end of this NSRegularExpression tutorial you will have implemented code to search for patterns in text, replace those matches with whatever you wish, validate user input information and find and highlight some complex strings in a block of text.
As a bonus, there is a regular expression cheat sheet that may come in handy:
To help you out, we have put together an official raywenderlich.com NSRegularExpression Cheat Sheet PDF for you!