FAQ Database Discussion Community

In c++11 what should happen first: raw string expansion or macros?

This code works in visual c++ 2013 but not in gcc/clang: #if 0 R"foo( #else int dostuff () { return 23; } // )foo"; #endif dostuff(); Visual C++ removes the if 0 first. Clang expands the R raw string first (and never defining dostuff). Who is right and why?...

Raw string and regular expression in Python

I have some confusions regarding raw string in the following code: import re text2 = 'Today is 11/27/2012. PyCon starts 3/13/2013.' text2_re = re.sub(r'(\d+)/(\d+)/(\d+)', r'\3-\1-\2', text2) print (text2_re) #output: Today is 2012-11-27. PyCon starts 2013-3-13. print (r'(\d+)/(\d+)/(\d+)') #output: (\d+)/(\d+)/(\d+) As how I understand the raw string, without r, the \...

Python - Raw String Literals

I don't understand how raw string literals work. I know that when using r it ignores all specials, like when doing \n it treats it as \n and not as a new line. but then I tried to do this: x = r'\' and it said SyntaxError: EOL while scanning...