匹配的正则表达式

Question

这是一个正常的寄存器名,可以是1-n个字符以a-zA-Z与-,像

larry-cai, larrycai, larry-c-cai, l,

但-不能像第一个和最后一个角色一样

-larry, larry-

我的想法是这样的

^[a-zA-Z]+[a-zA-Z-]*[a-zA-Z]+$

但如果我的正则表达式,长度应为2

应该很简单,但不要怎么做

如果你可以写它并通过http://tools.netshiftmedia.com/regexlibrary/会很好

Answer 1

您没有指定您正在使用的正则表达式引擎.一种方法是(如果您的引擎支持环视):

^(?!-)[A-Za-z-]+(?<!-)$

说明:

^           # Start of string  
(?!-)       # Assert that the first character isn't a dash
[A-Za-z-]+  # Match one or more "allowed" characters
(?<!-)      # Assert that the previous character isn't a dash...
$           # ...at the end of the string.

如果lookbehind不可用(例如在JavaScript中):

^(?!-)[A-Za-z-]*[A-Za-z]$

说明:

^           # Start of string  
(?!-)       # Assert that the first character isn't a dash
[A-Za-z-]*  # Match zero or more "allowed" characters
[A-Za-z]    # Match exactly one "allowed" character except dash
$           # End of string