from future import pass_function
steve+comp.lang.python at pearwood.info
Thu Jul 26 10:36:15 CEST 2012
On Thu, 26 Jul 2012 08:39:25 +0200, Ulrich Eckhardt wrote:
> I have seen code that just created a list comprehension to iterate over
> something but was discarding the results. That could be a case for a "do
> nothing" function.
That would be a case for *not* using a list comprehension.
Using a list comp when you don't want the results is the wrong way to do
it. That's like hammering a screw into a wall with a wrench. Okay, I
admit it, sometimes if I'm lazy and I'm in the interactive interpreter
and I need to consume use up results from an iterator, I type:
_ = [x for x in iterator]
and then I kick myself because I could have just written:
_ = list(iterator)
but in actual code, I'm not so lazy to bang that screw into the wall
using a wrench. I at least reach for a hammer:
_ = [None for x in iterator]
or better still, a drill:
But fine, you need a do-nothing function. Here you go:
_ = [(lambda x: None)(x) for x in sequence]
> Just having a function that does nothing would be useful in other
> places, too. In some cases, you want to print() some debug output in
> other cases you just use pass() to discard the debug output.
You're still not giving reasons why *pass* should be a do-nothing
function. Of course there are good use-cases for do-nothing functions,
that goes without saying. But you have to explain why:
1) that do-nothing function is so common and so important that it has to
be a built-in function; and
2) why it needs to be called "pass".
Nobody is disputing the usefulness of do nothing functions. We're
disputing that *pass* should be that function.
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