Hi to All,

Which is the way/best practice limiting _total_ length of an expression. I am validating data input with regex, phone email etc. For example given the following email regex:([A-Za-z0-9_%+-]\.?)+@([A-Za-z0-9-]+\.)+([A-Za-z0-9]{2,4}). I would like to limit to total length to 100 characters. 

thx for answers 

 

 

probably be quicker and easier to use your language construct for the length of the string like php's strlen or c# str.length test for <= 100 then run your regex otherwise you would have a rather bloated regex

You don't say what regex variant you are using so this may not work, but you could try prefixing the pattern with something like:

(?=^.{1,100}$)

This assumes that you want to limit the whole pattern to 100 (or whatever number you put in) characters, that you are counting characters (not treating "==" (say) as a single item) and that you are counting all characters.

This will check (but not move the match starting point or capture any text) that there is at least 1 character and at most 100 characters between the start and the end. If not then the pattern will fail. Otherwise, the rest of the pattern is tried as usual.

Susan