Inconsistent reaction to extend
fredrik at pythonware.com
Fri Sep 9 12:06:20 CEST 2005
Jerzy Karczmarczuk wrote:
> Gurus, before I am tempted to signal this as a bug, perhaps
> you might convince me that it should be so.
it's not a bug, and nobody should have to convince you about any-
thing; despite what you may think from reading certain slicing threads,
this mailing list is not an argument clinic.
> If I type
> l gives [0,1,2,3,1,2], what else...
> On the other hand, try
> Then, p HAS NO VALUE (NoneType).
(footnote: None is a value in Python. it can be used to represent "no value",
but it can also be used for other things)
> With append the behaviour is similar. I didn't try other methods, but
> I suspect that it won't improve.
because you're saving the return value of "extend", not "range", and "extend"
if you split it up like this
l = range(4)
p = l.extend([1, 2])
it should be obvious that "l" and "p" doesn't necessarily contain the same thing.
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