RegEx to make sure that the string contains at least one lower case char, upper case char, digit and symbol

user_165297 0
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What is the regex to make sure that a given string contains at least one character from each of the following categories.

  • Lowercase character
  • Uppercase character
  • Digit
  • Symbol

I know the patterns for individual sets namely [a-z], [A-Z], \d and _|[^\w] (I got them correct, didn't I?).

But how do I combine them to make sure that the string contains all of these in any order?

regex
4 Answers

Bart Kiers solution is good but it misses rejecting strings having spaces and accepting strings having underscore (_) as a symbol.

Improving on the Bart Kiers solution, here's the regex:

(?=.*\d)(?=.*[a-z])(?=.*[A-Z])((?=.*\W)|(?=.*_))^[^ ]+$

A short explanation:

(?=.*[a-z])        // use positive look ahead to see if at least one lower case letter exists
(?=.*[A-Z])        // use positive look ahead to see if at least one upper case letter exists
(?=.*\d)           // use positive look ahead to see if at least one digit exists
(?=.*\W)           // use positive look ahead to see if at least one non-word character exists
(?=.*_)           // use positive look ahead to see if at least one underscore exists
|           // The Logical OR operator
^[^ ]+$           // Reject the strings having spaces in them.

Side note: You can try test cases on a regex expression here.

user_140810180
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