Chapter 5, raw strings

[caoimhinoc]

Hi Mark,

I'm enjoying your book on python 3, but I don't understand the part in chapter 5 where you talk about raw strings. It seems that by adding r in front of '\bROAD$' you should achieve the opposite of what you want to, which is to have \b interpreted as a word boundary. Instead you'd get a slash followed by a b. In other words, why would you want the \ to be escaped here?

Except of course that the code works. But I don't know why it does. I'm suspecting it's because you want to ignore normal escape characters but not certain ones that the re module uses. Is that right?

[davipo]

You want a backslash in the string that you pass to the re.sub method, which interprets the "\b" as a boundary specifier. In a normal string, "\b" is a backspace character.