How to efficiently proceed addition and subtraction in pythonlist?

[Steve Holden]

Fredrik Lundh wrote:
> Steve Holden wrote:
> 
> 
>>And statements like that are probably going to annoy me ;-)
>>
>> >>> t = timeit.Timer("b = map(lambda x: x-1, a)", setup="a=[1,2,3]")
>> >>> t.timeit()
>>2.4686168214116599
>> >>> t = timeit.Timer("b = [x-1 for x in a]", setup="a=[1,2,3]")
>> >>> t.timeit()
>>0.9930245324475635
>> >>>
> 
> 
> And now someone's probably reading this and thinking that list comprehensions
> are *always* faster than "map"...
> 
You are so right. So, let me repeat the important part that Fredrik 
didn't quote:

"""if performance is *really* important, you
need to benchmark both options"""

regards
  Steve
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