[CentralOH] 2016-10-14 道場 Scribbles 落書/惡文? Part Three: list builder/list comprehension/generator function/generator expression/functional/; readability and optimization; chapter 20 lp

[jep200404 at columbus.rr.com]

Part Three:

The full version seems to have been caught in some filters,
so it is being reposted in smaller pieces.

common theme was converting list builder:
    foo = []
    for x in someiterable:
        foo.append(goo(x))
    return foo
to a comprehension
    return [goo(x) for x in someiterable]
to a generator function
    for x in someiterable:
        yield goo(x)
or a generator expression
    return (goo(x) for x in someiterable)
to a functional approach
    return map(goo, someiterable)
which of the above is easier for you to read?


N = 4
def grok():
    foo = []
    for x in someiterable:
        foo.append(goo(x))
    return foo[N:]

def grok():
    foo = (goo(x) for x in someiterable)
    return itertools.islice(foo, N, None)

which grok is easier for you to grok?
which handles arbitrarily large someiterable??

Read Chapter 20 of Learning Python, 5th edition by Mark Lutz


code for readability first
tweak for speed only if needed

    Premature optimization is the root of all evil.
    wp:Premature_optimization#When_to_optimize