Regex in Golang
Regular expression a.k.a Regex is a sequence of characters that define a search pattern
Cheat sheet
| Regexp | Meaning |
|---|---|
| xy | x followed by y |
| x|y | x or y, prefer x |
| xy|z | same as (xy)|z |
| xy* | same as x(y*) |
| ^ | matches the beginning of the string |
| $ | matches the end of the string |
| . | matches any single character except line break |
| * | matches the preceding expression zero or more times |
\d | any single digit character |
w | any word (alphanumeric & underscore) [0-9A-Za-z_] |
W | any character that is not a word [^0-9A-Za-z_] |
D | any character that is not a digit |
s | whitespace |
S | a non-whitespace character: [^ ] |
| [abc] | any single character from the character within the brackets |
| [a-z] | character set range from a to z |
| [abc]+ | one or more characters from the set |
| [^a-z] | match anything without the character range |
| + | one or more |
| {3} | exactly 3 times |
| {2,4} | 2 to 4 times |
| {3,} | 3 or more times |
| * | zero or more times |
| ? | once or none |
| x* | zero or more x, prefer more |
| x*? | prefer fewer (non-greedy) |
| x+ | one or more x, prefer more |
| x+? | prefer fewer (non-greedy) |
| x? | zero or one x, prefer one |
| x?? | prefer zero |
| x{n} | exactly n x |
| i | case-insensitive |
| m | let ^ and $ match begin/end line in addition to begin/end text (multi-line mode) |
| s | let . match (single-line mode) |