[Tutor] list comprehension equivalent to map(function, list item)

[Peter Otten]

Bo Morris wrote:

> Thank you for your assistance. Based on your direction, I figured it out.
> 
> *This... *
> 
> def add(number):
>      print 1 + int(number)
> 
> x = ['2', '4', '6', '8', '10', '12']
> 
> [add(item) for item in x]
> 
>  *Is the same as... *
> 
> 
> def add(number):
>      print 1 + int(number)
> 
> x = ['2', '4', '6', '8', '10', '12']
> 
> map(add, x)
> 
> They both yield the same results. Is there a benefit to using one way over
> the other? In larger computations, does one way calculate faster or is it
> merely a preference? Again, thank you.

For built-in functions map(f, items) is a bit faster. List-comps are more 
flexible; you can inline the function

>>> [int(s) + 1 for s in x]
[3, 5, 7, 9, 11, 13]

or add a filter:

>>> [int(s) + 1 for s in x if set("12") & set(s)]
[3, 11, 13]