On 24Jan2015 15:03, Mark Lawrence <breamore...@yahoo.co.uk> wrote:
On 24/01/2015 01:50, Cameron Simpson wrote:
My intuition is that a function is costly (potentially) and that
consulting an attribute is very cheap. I don't want to break such
intuition.
It's not just your intuition, it's a fact. Function calls are costly,
relative to attribute lookup that is, at least in cPython. I've no
idea what the impact is in other implementations. I'd guess that 99%
of the time 99% of Python programmers needn't worry about it.
Like Alan, you've missed my intent here.
To quote from my reply to Alan:
I am not referring to the overhead of making a function call, but the
intuitive cost that distinguishes something one thinks of as an attribute from
something one thinks of as a function: a function may entain an arbitrary
amount of work whereas an attibute is almost free, and constant in cost.
I'm not talking about optimisation here, I'm talking about the notion of a
value that is derived from (unspecified and perhaps costly) computation versus
a value that is merely stored, and trivially retrieved.
The an attribute/method/function very closely resembles the latter, I am prone
to make it into a property.
Cheers,
Cameron Simpson <c...@zip.com.au>
On two occasions I have been asked [by members of Parliament],
'Pray, Mr. Babbage, if you put into the machine wrong figures, will
the right answers come out?' I am not able rightly to apprehend the
kind of confusion of ideas that could provoke such a question.
- Babbage
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