| . |
Represents any single character |
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| [ ] |
Character set, giving a range of values for a single character |
[abc] means a, b, c, [az] means a to z single character |
| [^ ] |
Non-character set, the exclusion range is given for a single character |
[^abc] means a single character other than a or b or c |
| * |
Extend the previous character 0 times or unlimited times |
abc* means ab, abc, abcc, abccc, etc. |
| + |
Extend the previous character 1 time or unlimited times |
abc+ means abc, abcc, abccc, etc. |
| ？ |
0 or 1 expansion of the previous character |
abc? means ab, abc |
| | |
Any one of left and right expressions |
abc|def means abc, def |
| {m} |
Extend the previous character m times |
ab{2}c means abbc |
| {m,n} |
Extend the previous character m to n times (including n) |
ab{1,2}c means abc, abbc |
| ^ |
Match the beginning of the string |
^abc means abc and is at the beginning of a string |
| $ |
Match end of string |
abc$ means abc and is at the end of a string |
| ( ) |
Grouping mark, only the | operator can be used internally |
(abc) means abc, (abc|def) means abc, def |
| \\d |
Number, equivalent to [0-9] |
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| \\w |
Word character, equivalent to [A-Za-z0-9_] |
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