Tuple comprehension

[Tim Peters]

[brueckd at tbye.com]
> ...
> I'd *love* to have dictionary comprehensions!

Try this on for size:

>>> dict([(i, i**2) for i in range(10)])
{0: 0, 1: 1, 2: 4, 3: 9, 4: 16, 5: 25, 6: 36, 7: 49, 8: 64, 9: 81}
>>>

That is, 2.2 dict() accepts an iterable object producing iterable objects
each producing two values.  A list of 2-tuples is one instance of that, and
one particularly easy to create with a listcomp.  More possibilities open if
you ponder other kinds of iterable objects; e.g.,

>>> def squarepairs(n):
...     for i in range(n):
...         yield i, i**2
...
>>> dict(squarepairs(10))
{0: 0, 1: 1, 2: 4, 3: 9, 4: 16, 5: 25, 6: 36, 7: 49, 8: 64, 9: 81}
>>>

is one way to get the same end result without building a list in one gulp
first.