Java 分割正则表达式

Question

如何分割字符串

"-3.0*6.7+(5/2)*-0.8--12.98+4^-0.5"

通过使用正则表达式来

-3.0,*,6.7,+,(,5,/,2,),*,-0.8,-,-12.98,+,4,^,-0.5

Answer 1

使用正则表达式来完成此任务是不切实际的:您最好创建某种标记器/词法分析器来从输入源创建标记。特别是一元减号使得正则表达式分割变得困难。

但是为了回答你的问题，你可以按照以下模式进行划分:

(?=[+*/()^])|(?<=[+*/()^])|(?<=\d-)|(?<=\d)(?=-)

这意味着:

                # Split on:
(?=[+*/()^])    #   the empty space that has one of: +, *, /, (, ), ^ ahead of it
|               #   OR
(?<=[+*/()^])   #   the empty space that has one of: +, *, /, (, ), ^ before it 
|               #   OR
(?<=\d-)        #   the empty space that has a digit followed by a minus sign before it
|               #   OR
(?<=\d)(?=-)    #   the empty space that has a digit before it and a minus sign ahead of it