[Tutor] map vs. list comprehension

[Kent Johnson]

Michael Broe wrote:
> I read somewhere that the function 'map' might one day be deprecated  
> in favor of list comprehensions.
> 
> But I can't see a way to do this in a list comprehension:
> 
>  >>> map (pow, [2, 2, 2, 2], [1, 2, 3, 4])
> [2, 4, 8, 16]
> 
> Is there a way?

The current plan is to drop map() in Python 3.0 which is a "hypothetical 
future release of Python".
http://www.python.org/peps/pep-3000.html

List comps aren't so handy as a replacement for map() with a function of 
more than one argument. You have to use zip() to convert the separate 
arg lists to a single list of arg tuples:

  >>> [ pow(x, y) for x, y in zip([2, 2, 2, 2], [1, 2, 3, 4]) ]
[2, 4, 8, 16]

or if you prefer

  >>> [pow(*args) for args in zip([2, 2, 2, 2], [1, 2, 3, 4])]
[2, 4, 8, 16]

Kent