| Character |
Meaning |
Example |
| * |
Match zero, one or more of the previous |
Ah* matches "Ahhhhh" or "A" |
| ? |
Match zero or one of the previous |
Ah? matches "Al" or "Ah" |
| + |
Match one or more of the previous |
Ah+ matches "Ah" or "Ahhh" but not "A" |
| \ |
Used to escape a special character |
Hungry\? matches "Hungry?" |
| . |
Wildcard character, matches any character |
do.* matches "dog", "door", "dot", etc. |
| ( ) |
Group characters |
See example for | |
| [ ] |
Matches a range of characters |
[cbf]ar matches "car", "bar", or "far"
[0-9]+ matches any positive integer
[a-zA-Z] matches ascii letters a-z (uppercase and lower case)
[^0-9] matches any character not 0-9. |
| | |
Matche previous OR next character/group |
(Mon|Tues)day matches "Monday" or "Tuesday" |
| { } |
Matches a specified number of occurrences of the previous |
[0-9]{3} matches "315" but not "31"
[0-9]{2,4} matches "12", "123", and "1234"
[0-9]{2,} matches "1234567..." |
| ^ |
Beginning of a string. Or within a character range [] negation. |
^http matches strings that begin with http, such as a url.
[^0-9] matches any character not 0-9. |
| $ |
End of a string. |
ing$ matches "exciting" but not "ingenious" |