On Thu, 18 Nov 2010 09:32:23 +0000, Mark Wooding wrote:
[...]
> You're wrong. Python evaluates these left-to-right, as I said.
> Parentheses override operator associativity; they don't affect
> evaluation order at all.
Fair enough. I concede your point.
[...]
>> Not everything needs to be a one liner. If you need this, do it the
>> old- fashioned way:
>>
>> t = foo()
>> if not pred(t): t = default_value
>
> I already explained how to write it as a one-liner:
>
> t = (lambda y: y if pred(y) else default_value)(foo())
I didn't say it couldn't be written as a one-liner. I suggested that it
was better not to.
The costs of the one-liner are:
* reduced readability;
* requires an increased level of knowledge of the reader ("what's lambda
do?");
* runtime inefficiency (you create a function object, only to use it once
then throw it away).
The advantages?
* one fewer line of code.
In my experience, the obsessiveness in which some people look for one-
liners is far from helpful, and goes against the spirit of Python. This
isn't Perl :)
--
Steven
--
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