RegEx to Validate Password (1 Lowercase, 1Uppercase, 1 Digit, NoSpaces)

Question

I'm trying to create a RegExpression to meet the criteria below;

• at least 1 Lowercase
• at least 1 Uppercase
• at least 1 Digit
• No Spaces
• Minimum 8 characters
• No special characters

So far I got this;

^(?=.{8,})(?=.*[a-z])(?=.*[A-Z])(?=.*\d)(?=.\s).*$

However I can not get it to work. Any help would be greatly appreciated. I was never good at puzzles :)

Answer 1

You're nearly there; it's just the .* at the end that ignores your "no spaces/special characters" rules, and the (?=.\s) lookahead is wrong (you probably meant (?!.*\s) or (?=\S*$)).

But you don't need that lookahead anyway because you can simply specify which characters are allowed (and enforce the "8 characters minimum" rule there, too):

^(?=.*[a-z])(?=.*[A-Z])(?=.*\d)[A-Za-z\d]{8,}$

But why do you want to keep users from using non-alphanumeric characters in their passwords?