So you want *x behave radically different in subtly different contexts?
a, *x, b = iterator
would give x a list and iterator run to exhaustion, whereas:
Using the infix "*x" I'd be fine with x being an iterator too in
the same way as the postfix "*x" I'd enjoy, but this would
require consuming all-but-the-remaining-fixed and the converting
the middle bits back into an iterator...which isn't that much
different from the current implementation of "a, *x, b = itr" with
x = iter(x)
after the tuple assignment. Not a great gain, but at least
consistent to remove that burr.
It doesn't allow for infinite generators, but that's a somewhat
nonsensical request anyways :) "b = INF"? "b=-INF"? "b=K"?
and it gets weirder with
a,*x,b,c,d = inf_seq_of_monotonically_increasing_primes()
if you can get me b, c, and d in a finite amount of time, you get
some sorta prize :)
However, having some syntax giving the behaviour you want would be nice.
Something like this perhaps?
a, b, c = *iterable
equivalent to:
_t = iter(iterable)
a = next(_t)
b = next(_t)
c = next(_t) # and so on for each of the left-hand names
del _t
That would be useful.
But yes, that's even better for my use case, as it lacks the ugly
"*_" sponge to soak up the remainder and removes my need to track
the number of items on the LHS of the assignment. That seems it
would involve a new Python construct/syntax rather than the
existing py3k syntax. Or at least the removal of the
"ValueError: too many values to unpack" error. That would be a
lovely addition (when the new-feature-ban is lifted :)
-tim
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