regex.md

image.svg

regex.md

Regex tricks

https://regexper.com image.svg is from there

regex visualizer

exrex: generate words from regex

regexr: teaching

http://www.pyregex.com/

---

- negative lookahead: ^(?!.*bar).*$

e.g.: cut out "id": n in json

^(?!.*("id": ".*.")).*$

- passwords: 

             ^(?=.*?[A-Z]{2,})  # min. 2 upper case
              (?=.*?[a-z]{2,})  # min. 2 lower case
              (?=.*?[0-9]{2,})  # min. 2 numericals
              .{8,8}$           # length between 8,8 => 8
              
              ^(?=.*?[A-Z]{2,})(?=.*?[a-z]{2,})(?=.*?[0-9]{2,})(?!.*(.).*\1).{8,8}$ 
              
              inserting (?!.*(.).*\1) constraints word to be only of unique characters
              
            (
               (
               (
                (?=.*?[A-Z]
               ).{2,}
              )
              (
                (?=.*?[a-z])
                .{2,}
              )
              (
                (?=.*?[0-9])
                .{2,}
              )
                )(?!.*(.).*\1)
            )
            .{8,8}$ 
            
            => ((((?=.*?[A-Z]).{2,})((?=.*?[a-z]).{2,})((?=.*?[0-9]).{2,}))(?!.*(.).*\1)).{8,8}$