What’s the difference between () and [] in regular expression patterns?

by

[] denotes a character class. () denotes a capturing group.

[a-z0-9] — One character that is in the range of a-z OR 0-9

(a-z0-9) — Explicit capture of a-z0-9. No ranges.

a — Can be captured by [a-z0-9].

a-z0-9 — Can be captured by (a-z0-9) and then can be referenced in a replacement and/or later in the expression.

More Related Contents:

  1. How does the () and [] come into play with regex?
  2. Regular Expression for ” – ” and characters after [closed]
  3. What is this pattern “\\s*\\^++\\s*” used for? [duplicate]
  4. How do (*SKIP) or (*F) work on regex?
  5. Regular Expression to find a string included between two characters while EXCLUDING the delimiters
  6. Difference between * and + regex
  7. Regex to validate JSON
  8. Regex to match only letters
  9. How to calculate the number of occurrence of a given character in each row of a column of strings?
  10. Regular expression to enforce complex passwords, matching 3 out of 4 rules
  11. Regular expression for a string that does not start with a sequence
  12. How can I use a variable in the replacement side of the Perl substitution operator?
  13. Why doesn’t `\d` work in regular expressions in sed? [duplicate]
  14. Regex to match all permutations of {1,2,3,4} without repetition
  15. Regular expression for youtube links
  16. How can I use ‘Not Like’ operator in MongoDB
  17. Negate characters in Regular Expression [closed]
  18. Zero-Length regexes and infinite matches?
  19. Regex pattern for HH:MM:SS time string
  20. sed join lines together
  21. Why is sed not recognizing \t as a tab?
  22. Symbol for any number of any characters in regex?
  23. Match Question Mark in mod_rewrite rule regex
  24. Dollar sign in regular expression and new line character
  25. How to use RegEx in Dart?
  26. Regex for youtube URL
  27. .htaccess RewriteRule to path without changing URL
  28. What do \S, \W, \D stand for in regex?
  29. Regexp for subdomain
  30. Regex for field that allows numbers and spaces

Leave a Comment