2.1 KiB
2.1 KiB
| title | category | layout | weight | authors | updated | description | ||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| regexp | Others | 2017/sheet | -1 |
|
2019-03-24 | Basic cheatsheets for regular expression |
{: .-three-column}
Character classes
| Pattern | Description |
|---|---|
. |
Any character, except newline |
\w |
Word |
\d |
Digit |
\s |
Whitespace |
\W |
Not word |
\D |
Not digit |
\S |
Not whitespace |
[abc] |
Any of a, b, or c |
[a-e] |
Characters between a and e |
[1-9] |
Digit between 1 and 9 |
Anchors
| Pattern | Description |
|---|---|
^abc |
Start with abc |
abc$ |
End with abc |
Escaped characters
| Pattern | Description |
|---|---|
\. \* \\ |
Escape special character used by regex |
\t |
Tab |
\n |
Newline |
\r |
Carriage return |
Groups
| Pattern | Description |
|---|---|
(abc) |
Capture group |
Quantifiers
| Pattern | Description |
|---|---|
a* |
Match 0 or more |
a+ |
Match 1 or more |
a? |
Match 0 or 1 |
a{5} |
Match exactly 5 |
a{,3} |
Match up to 3 |
a{3,} |
Match 3 or more |
a{1,3} |
Match between 1 and 3 |
Lookahead & Lookbehind
| Pattern | Description |
|---|---|
a(?=b) |
Match a in baby but not in bay |
a(?!b) |
Match a in Stan but not in Stab |
| --- | --- |
(?<=a)b |
Match b in crabs but not in cribs |
(?<!a)b |
Match b in fib but not in fab |