Regular Expressions¶
regex = regular expression
Synthax¶
| Sign | Explanation | Expression | String containing the expression |
|---|---|---|---|
^foo |
string beginning with ‘foo’ | ^foo | ‘foobar’, ‘foo’ |
bar$ |
string ending with ‘bar’ | bar$ | ‘foobar’, ‘bar’ |
* |
0, 1 or more | abc* | ‘ab’, ‘abc’, ‘abcc’, ‘abcccccc’ |
+ |
1 or more | abc+ | ‘abc’, ‘abcc’, ‘abccc’ |
? |
0 or 1 | abc? | ‘ab’, ‘abc’ |
{n} |
n times ‘c’ | abc{4} | ‘abcccc’ |
{n,m} |
n to m times ‘c’ | abc{2,4} | ‘abcc’, abccc’, abcccc’ |
{,m} |
0 to m times ‘c’ | abc{,4} | ‘ab’, ‘abc’, ‘abcc’, abccc’, abcccc’ |
{n,} |
n or more times ‘c’ | abc{,2} | ‘abcc’, ‘abccc’, ‘abcccc’ |
[abcd] |
‘a’ or ‘b’ or ‘c’ or ‘d’ | abc[abcd] | ‘abca’, ‘abcb’, ‘abcc’, ‘abcd’ |
[a-d] |
any char between ‘a’ and ‘d’ | abc[a-d] | ‘abca’, ‘abcb’, ‘abcc’, ‘abcd’ |
[a-d]{n} |
n times any char btw ‘a’ and ‘d’ | abc[a-d]{2} | ‘abcab’, ‘abcbd’, ‘abccc’, ‘abcdd’ |
(abc){n} |
n times the string ‘abc’ | abc(def){2} | ‘abcdefdef’ |