Re[4]: backslashes and r-strings r"abc"

On Tue, 27 Jul 2004 11:17:29 -0700 Mark Hahn <[email protected]> wrote:

> Lenard Lindstrom wrote:
> 
> >> Mark Hahn <[email protected]>:
> >> 
> >>> Does anyone see any reason to preserve Python's restriction on not 
> >>> having a backslash as the last character of a r-string?
> >> 
> >> The reason it's there is because, even inside r-strings, backslashes 
> >> still escape quote characters. To remove it, you'd have to either 
> >> disallow quotes embedded in r-strings, or come up with some 
> >other way 
> >> of flagging them without compromising the rawness quality of 
> >> r-strings.
> >> 
> >Backslashes are not removed in raw strings. So a 
> >backslash-quote gives you that, a backslash-quote. Hardly 
> >useful for including double quotes in a single quoted string 
> >or vice versa.
> 
> Well, it IS useful if the quote character you need happens to follow a
> backslash. :-)
> 
> No wonder I didn't understand what "Python in a nutshell" was explaining.
> It makes no sense whatsoever.  What in the hell was Guido thinking?
> 
Regular expressions. Martin Christensen mentioned only using "r" strings for
regular expressions. That is where I use them too. A backslash-quote in a
pattern will match a quote in a string. And two backslashes are required
to match a single backslash. Thus the even number of backslashes at the
end of an "r" string rule. So "r" for "regular expression" makes sense;
"r" for "raw" does not.

Lenard Lindstrom
<[email protected]>