list problem

[placid]

Simon Forman wrote:
> placid wrote:
> > Hi all,
> >
> > I have two lists that contain strings in the form string + number for
> > example
> >
> > >>> list1 = [ ' XXX1', 'XXX2', 'XXX3', 'XXX5']
> >
> > the second list contains strings that are identical to the first list,
> > so lets say the second list contains the following
> >
> > >>> list1 = [ ' XXX1', 'XXX2', 'XXX3', 'XXX6']
> >
> > and now what ive been trying to do is find the first string that is
> > available,
> > i.e a string that is in neither of the two lists so the following code
> > should only print XXX4 then return.
> >
> > for i in xrange(1,10):
> >     numpart = str(1) + str("%04i" %i)
> >     str = "XXX" + numpart
> >
> >       for list1_elm in list1:
> >           if list1_elm == str:
> >                break
> >           else:
> >                for list2_elm in list2:
> >                    if list2_elm == str:
> >                       break
> >                    else:
> >                       print str
> >                       return
> >
> > Cheer
>
> Well first off, don't use 'str' for a variable name.
>
> Second, "%04i" % i creates a string, don't call str() on it.
>
> Third, str(1) will always be "1" so just add that to your format string
> already "1%04i" % i
>

thanks for the tips

> (And if the "XXX" part is also constant then add that too: "XXX1%04i" %
> i)
>
> Finally, you can say:
>
> for i in xrange(1,10):
>     s = "XXX1%04i" % i
>     if s not in list1 and s not in list2:
>         print s
>

But there may be other characters before XXX (which XXX is constant). A
better example would be, that string s is like a file name and the
characters before it are the absolute path, where the strings in the
first list can have a different absolute path then the second list
entries. But the filenames are always exact. So you need to split the
entries bases on "\\" (windows machine) and match on this ?


Cheers