Gregory Petrosyan wrote:
> Hello!
> I have a question for the developer[s] of enumerate(). Consider the
> following code:
>
> for x,y in coords(dots):
> print x, y
>
> When I want to iterate over enumerated sequence I expect this to work:
>
> for i,x,y in enumerate(coords(dots)):
> print i, x, y
>
> Unfortunately, it doesn't =( and I should use (IMHO) ugly
>
> for i,pair in enumerate(coords(dots)):
> print i, pair[0], pair[1]
>
> So, why enumerate() works this way and is there any chance of changing
> the behaviour?
It works that way because enumerate returns a tuple - index, value. And it
doesn't care what is inside value. Actually, it can't - how would you then
write something like this?
l = [1, ('a', 'tuple'), 3]
for i, value in enumerate(l):
print i, value
But your problem can be solved in an elegant fashion anyway. When *you* know
the structure of the values (and who else does?), you can simply use nested
sequence unpacking:
for i, (x, y) in enumerate(coords):
pass
HTH,
Diez
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