map is useless!

[Roald de Vries]

On Jun 6, 2010, at 5:16 PM, rantingrick wrote:
> Everyone knows i'm a Python fanboy so nobody can call me a troll for
> this...
>
> Python map is just completely useless. For one it so damn slow why
> even bother putting it in the language? And secondly, the total "girl-
> man" weakness of lambda renders it completely mute!
>
> Ruby has a very nice map
>
>>>> [1,2,3].map{|x| x.to_s}
>
> Have not done any benchmarking but far more useful from the
> programmers POV. And that really stinks because map is such a useful
> tool it's a shame to waste it. Here are some test to back up the rant.
>
>
>>>> import time
>>>> def test1():
> 	l = range(10000)
> 	t1 = time.time()
> 	map(lambda x:x+1, l)
> 	t2= time.time()
> 	print t2-t1
>
>
>>>> def test2():
> 	l = range(10000)
> 	t1 = time.time()
> 	for x in l:
> 		x + 1
> 	t2 = time.time()
> 	print t2-t1
>
>
>>>> test1()
> 0.00200009346008
>>>> test2()
> 0.000999927520752
>>>> def test3():
> 	l = range(10000)
> 	t1 = time.time()
> 	map(str, l)
> 	t2= time.time()
> 	print t2-t1
>
>
>>>> def test4():
> 	l = range(10000)
> 	t1 = time.time()
> 	for x in l:
> 		str(x)
> 	t2= time.time()
> 	print t2-t1
>
>
>>>> test3()
> 0.00300002098083
>>>> test4()
> 0.00399994850159
>>>>
>
> So can anyone explain this poor excuse for a map function? Maybe GVR
> should have taken it out in 3.0?  *scratches head*

Use list comprehension. It's nicer than Ruby's map:

[x.to_s for x in 1, 2, 3]