Regular Expressions 101

Community Patterns

Community Library Entry

1

Regular Expression
PCRE (PHP <7.3)

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# Adding password requirements are as easy as tacking on # another (?=...) group. ^ (?=(?:[^a-z]*[a-z]){1}) # At least {1} lowercase 'a-z' letter (?=(?:[^A-Z]*[A-Z]){2}) # At least {2} uppercase 'A-Z' letters (?=(?:[^0-9]*[0-9]){3}) # At least {3} digits (?=(?:[^\s]*[\s]){1}) # At least {1} whitespace (?=(?:[^[:punct:]]*[[:punct:]]){1}) # At least {1} special char (?=.{9}) # A minimum of 9 characters
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gmx

Description

Password requirements (minimum length, character groups that must exist) can be easily validated AND extended using look-aheads.

Submitted by OnlineCop - 8 years ago