[Python-Dev] Why both r'' and R'', u'' and U''?

[Ka-Ping Yee]

On Sun, 14 Jan 2001, Guido van Rossum wrote:
> 
> It comes from the numeric literals.  C allows 0x0 and 0X0, and 0L as
> well as 0l.  So does Python (and also 0j == 0J).

I just did a little test.  Neither Python, Perl, nor Tcl support
"\X66", only "\x66".  Perl doesn't support 0X1234, only 0x1234.
Tcl's "expr" routine does support 0X1234.  Javascript supports
0X1234, but not "\X66".  I'd bet that no one really relies on or
expects the uppercase forms except L.


-- ?!ng