CODEWITHSUNDEEP
regexbash
ibz
ibz

Reputation: 77

Regex for 1 or more letters numbers, and exactly one special char

I need help with a Regex for 1 or more lowercase letters, 1 or more uppercase letters , 1 or more digits, and exactly 1 special character.

I wrote this so far:

^(?=.*\d)(?=.*[a-z])(?=.*[A-Z])(?=.*[\@\#\^])[a-zA-Z0-9\@\#\^]*$

It gets more than one special character. By the way I'm using grep -P, and I'm testing my regex's with http://regexr.com/ first.

I forgot to mention that the characters should be in any order.

Upvotes: 1

Views: 1495

Answers (1)

R Nar
R Nar

Reputation: 5515

separate your special characters to a different character class that only matches once:

^(?=.*\d)(?=.*[a-z])(?=.*[A-Z])[a-zA-Z0-9]*[\@\#\^][a-zA-Z0-9]*$
#NOTES:                       ^you dont need to do a look ahead for the special char since you explicitly match only 1

 (?=...) ...                 ) signifies lookaheads: they each check that there is at least
one number, lowercase, and uppercase letter in the following match 
                               [a-zA-Z0-9]* matches 0 or more of those for as long as possible
                                           [\@\#\^] matches exactly one of these characters
                                                    [a-zA-Z0-9]* matches any of the remaining characters

this works better than the original because it ensures that one, and only one, special character is matched

Upvotes: 2

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