Question

I need to write regex that check following words: must start with a letter, may contain {3,16} numbers and\or letters.

I tried the following regex \b[A-Za-z]+[A-Za-z0-9]*{3,16}\b, but I get error.
What is wrong?

Answer 1

You are getting the error because of the *. Remove it to get a valid regex:

\b[A-Za-z]+[A-Za-z0-9]{3,16}\b

However, this regex isn’t quite what you want, which is:

\b[A-Za-z][A-Za-z0-9]{2,15}\b

You need {2,15} (and not {3,16}) because the first character counts for one of the {3,16}