Why does extend() fail in this case, and what am I doing wrong?
MRAB
python at mrabarnett.plus.com
Tue Jul 14 11:13:43 EDT 2009
Xavier Ho wrote:
> Why doesn't the second output print [1, 2, 3, .... , 7, 8, 9] ?
> The code is run at: http://codepad.org/wgLU4JZh
>
> class A():
> def __init__(self):
> self.n = [1, 2, 3, 4, 5]
>
> a = A()
> print a.n
> print a.n.extend([6, 7, 8, 9])
>
> #Output:
> #[1, 2, 3, 4, 5]
> #None
>
> I really don't know, but I'm probably missing something. Any pointers
> would be great.
>
The extend() method modifies the list in-place and returns None. Try
printing a.n after extending.
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