Fear and suspicion of lambdas, was Re: Meta decorator with parameters, defined in explicit functions
Peter Otten
__peter__ at web.de
Thu Jun 30 03:25:20 EDT 2016
Lawrence D’Oliveiro wrote:
> On Tuesday, June 28, 2016 at 5:03:08 PM UTC+12, Ben Finney wrote:
>
>> I would like to see a more Pythonic, more explicit and expressive
>> replacement with its component parts easily understood.
>
> I don’t know why this fear and suspicion of lambdas is so widespread among
> Python users ... former Java/C# programmers, perhaps?
If there is "fear" I don't share it. However, for
foo = lambda <args>: <expr>
there is syntactic sugar in Python that allows you to write it as
def foo(<args>):
return <expr>
with the nice side effects that it improves the readability of tracebacks
and allows you to provide a docstring.
So yes, assigning a lambda to a name raises my "suspicion".
If a lambda is provided as an argument or as part of an expression I wonder
how it is tested, and if even if it is trivial like
def reduce(items, func=lambda x, y: x + y): ...
the alternative
def reduce(items, func=add): ...
looks more readable in my eyes even though somewhere -- under the rug or in
the operator module -- you need
def add(x, y):
"""
>>> add(3, 4)
7
"""
return x + y
>> decorator_with_args = lambda decorator: lambda *args, **kwargs:
lambda func: decorator(func, *args, **kwargs)
>
> Ah, I see why there are 3 lambdas, instead of 2. It’s so that you can
write
I have a suspicion that there would not have been a correction "I see why
there are three functions instead of two" ;)
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