Regular Expression Syntax Examples
Table 15-6 is a comprehensive table of all the regular expressions we've covered. Column one contains example expressions, and column two contains what each expression will match.
Table 15-6. Complete list of regular expression examples
Expression |
Will match . . . |
---|---|
foo |
The string "foo" |
^foo |
"foo" at the start of a line |
foo$ |
"foo" at the end of a line |
^foo$ |
"foo" when it is alone on a line |
[Ff]oo |
"Foo" or "foo" |
[abc] |
a, b, or c |
[^abc] |
d, e, f, g, V, %, ~, 5, etc.âeverything that is not a, b, or c (^ is "not" inside character classes) |
[A-Z] |
Any uppercase letter |
[a-z] |
Any lowercase letter |
[A-Za-z] |
Any letter |
[A-Za-z0-9] |
Any letter or number |
[A-Z]+ |
One or more uppercase letters |
[A-Z]* |
Zero or more uppercase letters |
[A-Z]? |
Zero or one uppercase letters |
[A-Z]{3} |
Three uppercase letters |
[A-Z]{3,} |
A minimum of three uppercase letters |
[A-Z]{1,3} |
One, two, or three uppercase letters |
[^0-9] |
Any non-numeric character |
[^0-9A-Za-z] |
Any symbol (not a number or a letter) |
(cat|sat) |
Matches either "cat" or "sat" |
([A-Z]{3}|[0-9]{4}) |
Matches three letters or four numbers |
Fo* |
F, Fo, Foo, Fooo, Foooo, etc. |
Fo+ |
Fo, Foo, Fooo, Foooo, etc. |
Fo? |
F, Fo |
. |
Any character except \n (new line) |
\b |
A word boundary; e.g. te\b matches the "te" in "late" but not the "te" in "tell." |
\B |
A non-word boundary; "te\B" matches the "te" in "tell" but not the "te" in "late." |
\n |
Newline character |
\s |
Any whitespace (new line, space, ... |
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