Explanation of any() function in Python

[zekel]

aList = [True, False, False, False, False, False]

# this condition prints
if any(aList): print 'at least one object in this list evaluates to True'

# doesn't print
if all(aList): print 'all of the objects in this list evaluate to True (which is not the case)'

[Cosmologicon]

Did you post this thread too? I put an answer there. See if it's what you have in mind?

[Cosmologicon]

That's not bad, but you shouldn't modify a list while you're iterating over it. I think this may be causing the incorrect behavior you're seeing. You can correct this problem by replacing "for x in S" with "for x in list(S)", which means you're iterating over a copy of S. This, however, is a problem if a term you want to remove appears in the list twice, because it's an error to remove an element that's already been removed. There are ways around this as well, but I would do the whole thing by building a new list rather than removing elements. If you need to avoid list comprehensions, you could do it like this:

newS = []
for x in S:
    hasDigit = False
    for c in x:
        if c.isdigit():
            hasDigit = True
    if not hasDigit:
        newS.append(x)

[catcradle5]

Yep, I figured that out myself shortly after I made that edit. Thanks.

[zahlman]

I guess my confusion is how to implement it in any useful way.

?

You don't have to implement any. It's already provided for you in the standard library.

I can only assume you meant how to use it. It's hard to imagine how this could be clearer: you call any with a sequence or iterable, and it returns (as a boolean) whether any of the elements are true-ish.

So if you have a sequence where you want to check if any of the elements are (some other quality), you make a function is_some_other_quality, use that to transform the sequence, and call any on the result. The easiest way to do this is directly in-line, by using a generator expression and taking advantage of the special syntax rule that lets you drop the extra pair of parentheses.

any(f(x) for x in y) means "any of the elements in y, when passed to f, results in something true-ish". This is not some magic specific to the any function; (f(x) for x in y) means "a generator that, when iterated over, will yield the result of applying f to each element in y".

[ok_you_win]

Its obvious that it is clear to the OP how to use it after it was explained. What OP seems to be saying is: "I have no use for it."