list-comprehension and map question (simple)

[Robert Kern]

runsun pan wrote:
> I remember reading somewhere that the map, filter, reduce are much
> faster than list comp.

It depends.

   map(float, some_list_of_numbers)

is going to be faster than

   [float(x) for x in some_list_of_numbers]

but

   map(lambda x,y: x+y, xs, ys)

is going to be slower than

   import itertools
   [x+y for x,y in itertools.izip(xs, ys)]

-- 
Robert Kern
rkern at ucsd.edu

"In the fields of hell where the grass grows high
  Are the graves of dreams allowed to die."
   -- Richard Harter