Regex Basic

Quantifier

*

A character appears 0 or more times.

+

A character appears 1 or more times.

{3}

A character appears 3 times.

{2,6}

A character appears 2~6 times. [2, 6].

{2, }

A character appears more than 2 times. [3, +∞).

Multi-Character

OR

Character Type

[abc]

[a-z]

[a-zA-Z]

[a-zA-Z0-9]

Non

[^0-9]

Meta-Character

\d = [0-9]
\D =[^0-9]
\w = [a-zA-Z0-9_]
\W = [^a-zA-Z0-9_]
\s = space
\S = non space
.* = any character, except for link break.

^ Start of string

$ End of string

Greedy Match

Lazy Match

Practice

• Match the cache template:

bundle{{.Bundle}}:{{.Country}}:sessionid{{mod .Sessionid 32}}:shopid{{mod .Shopid32}}:itemid{{.Itemid}}

regex: ([a-z]*){{([\w\s.]+?)}}

A great regex tool is used in this blog, which is regex101.

Ref:

1. https://www.bilibili.com/video/BV1da4y1p7iZ?spm_id_from=333.337.search-card.all.click
2. https://github.com/ziishaned/learn-regex/tree/master/translations
3. 正则表达式30分钟入门教程 作者: deerchao https://deerchao.cn/tutorials/regex/regex.htm
4. Regex tutorial — A quick cheatsheet by examples (英文) 作者: Jonny Fox https://medium.com/factory-mind/regex-tutorial-a-simple-cheatsheet-by-examples-649dc1c3f285
5. Regular Expressions Tutorial (英文) https://www.regular-expressions.info/tutorial.html