map/filter/reduce/lambda opinions and background unscientific mini-survey

[Steven D'Aprano]

On Sat, 02 Jul 2005 20:26:31 -0700, Devan L wrote:

>  Claiming that sum etc. do the same job is the whimper of
> someone who doesn't want to openly disagree with Guido.
> 
> Could you give an example where sum cannot do the job(besides the
> previously mentioned product situation?

There is an infinite number of potential lambdas, and therefore an
infinite number of uses for reduce.



sum only handles a single case, lambda x,y: x+y

product adds a second case: lambda x,y: x*y

So sum and product together cover precisely 2/infinity, or zero percent,
of all possible uses of reduce.


> Also, map is easily replaced.
> map(f1, sequence) == [f1(element) for element in sequence]

Three mental tokens ( map, f1, sequence ) versus seven ( [], f1, element,
for, element, in, sequence ).

Also, map can take any number of sequences:

map(f1, seq1, seq2, seq3, seq4, ...)


-- 

Steven.