Regular Expressions (regexp) are used for pattern matching in searches. They are best used in finding and replacing features. * Regular Expressions Quick Reference
Commonly Used
| Action | Format | Example | Result |
|---|---|---|---|
| Wildcard | . | a.e | Will find "ate", "are", "ale", etc |
| Match previous element zero or more times | * | b.*t | Will find any characters between b and t, "bent", "beet", "belt", "boot", etc |
| Match previous element one or more times | + | be+ | Will find "bee", "be", "been", "bent", etc |
| Match previous element zero or one time | ? | rai?n | Will find "rain", "ran", etc |
| Match previous element n times | {n} | \d{3} | Will find "043", "999", "877", "001", etc |
| Match previous element at least n times but not more than m times | {n,m} | \d{1,3} | Will find "0", "04", "975", "34", "320", "9", etc |
| Digit | \d | \d\d.\d | Will find "19.0", "23.4", "03.9", etc |
| Word | \w | .\w23 | Will find ".M23", ".p23", ".A23", ".c23", etc |
| End of String | $ | 333$ | Will find "1296-1333", "panda 333", "901-333", etc |
| Start of String | ^ | ^333 | Will find "333 panda", "3330-4000", "333-901", etc |
| Replacing Expressions | () and $1 | Find: (=856.*\$u)(.*)(\$z.*) Replace: $1http://www.google.com$3 | Will change "=856 \\$uhttp://library.brown.edu$zpublic note" to "=856 \\$uhttp://www.google.com$zpublic note" |
| Match Single character in a group | [x] | [aei] | Will find "a" in "Gray" or "a" and "e" in "lane" or "i" in "kid" |
| Match single character in a group within a range between n and m | [n-m] | [A-Z] | Will find "A", "C", "T", etc |
| Match single character not in a group | [^x] | [^aei] | Will find "group", "loot", "hunt", etc |
