java - 正则表达式 [1-57-9] 是如何解释的？

Question

这是在 Java 中:[1-57-9]

我今天遇到了这个正则表达式，我正试图找出它的确切含义。有人可以帮我吗？

Answer 1

它允许使用数字 1-5 和 7-9。所以它等同于 [12345789]。

请参阅 Pattern 的文档有关 Java 中正则表达式的详细信息，特别是“字符类”下的示例:

• [abc] - a, b, or c (simple class)
• [^abc] - Any character except a, b, or c (negation)
• [a-zA-Z] - a through z or A through Z, inclusive (range)
• [a-d[m-p]] - a through d, or m through p: [a-dm-p] (union)
• [a-z&&[def]] - d, e, or f (intersection)
• [a-z&&[^bc]] - a through z, except for b and c: [ad-z] (subtraction)
• [a-z&&[^m-p]] - a through z, and not m through p: [a-lq-z] (subtraction)

另见 regular-expressions.info网站及其 section on character classes .