Am Wed, 17 Dec 2008 11:17:14 -0500
schrieb "Kent Johnson" <ken...@tds.net>:
> On Wed, Dec 17, 2008 at 10:20 AM, ppaarrkk <simon_...@yahoo.co.uk>
> wrote:
> >
> > I can do this :
> >
> >>>> sys.path.append ( 'C:\dump1' )
>
> Note you should use raw strings r'C:\dump1' or double backslash
> 'C:\\dump1' because the \ is a string escape character.
>
> > but not :
> >
> >>>> x = 'C:\dir1'
> >>>> sys.path.append(x)
>
> That should work fine (other than the single \). What happens when
> you try it?
>
> > or :
>
> ??
>
> > but not :
>
> >>>> x = ['C:\dir1']
> >>>> sys.path.append(x)
>
> Here you are appending a list of strings to sys.path, that will not do
> what you want.
The correct thing to do if you want to add a list of paths to sys.path
(btw, that probably is not what you want in real life, but that's a
complete different question.), you should do
sys.path.extend(x)
which is an efficient way to do
for i in x:
sys.path.append(i)
Or to visualize it with something simpler:
a = [1, 2, 3]
b = [4, 5, 6]
c = 7
a # [1,2,3]
a.append(c)
a # [1,2,3,7]
a.append(b)
a # [1,2,3,7,[4,5,6]]
a.extend(b)
a # [1,2,3,7,[4,5,6],4,5,6]
Basically append just appends it's parameter to the list, and if the
parameter happens to be a list, it appends the list as one item. Extend
on the other hand, appends all iterable items in the parameter to the
list.
Andreas
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