中缀到后缀的正则表达式

Question

I came across following line while going through code that converts infix expression to postfix.

string pattern = @"(?<=[^\\\\.a-zA-Z\\\\d])|(?=[^\\\\.a-zA-Z\\\\d])"

Could not quite get what "\\\\" in above regular expression is worth while converting something like ((a+(b*(f/c)))-e) to abfc/*+e-

Answer 1

When the value gets assigned to the string, it will become \\. which means you are literally looking for a .

In regular expression . matches any character, where as here, \\. will match a . character literally.