这个perl正则表达式匹配什么？

Question

我已经开始学习正则表达式,但它有很多元素.它匹配什么？

$x =~s/\.?0+$//;

Answer 1

它从字符串末尾删除句点和尾随零,将'24 .00'更改为'24'.碎片:

s/  substitute operation
\.  literal period, not a placeholder
?   Period is optional (by the way, probably a bug)
0+  one or more zeros
$   all of this at the end of the string.
//  replace it with nothing, i.e.,  just delete it.

错误？好吧,'2400'将改为'24'.可能不是理想的行为.

Answer 2

它匹配零个或一个文字点,后跟一个或多个零,然后是字符串的结尾.

\.     #A literal dot
?      #Zero or one of the previous character
0+     #One or more zeros
$      #End of string