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Re: Python-list Digest, Vol 109, Issue 20

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Benjamin Jessup

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Oct 4, 2012, 8:20:00 AM10/4/12
to pytho...@python.org
On 10/4/2012 12:20 AM, python-li...@python.org wrote:
> How do you know that?
>
> No offence, but if you can't even work out whether lookups in a dict or a
> list are faster, I can't imagine why you think you can intuit what the
> fastest way to retrieve the nearest neighbours would be.

Whats wrong with the test below?

# randomly select matrix coordinates to look-up
from random import randrange
test_coords = []
for i in range(1000):
x = randrange(2400); y = randrange(2400); test_coords.append((x,
y))

# build objects
class Object():pass
obj1 = Object(); obj2 = Object(); obj1.up = obj2

# build some test code
from timeit import Timer
setup = "from __main__ import test_coords, obj1, obj2"
t = Timer("for p in test_coords: obj = obj1.up", setup)

# run the test code
print(min(t.repeat(number=10000, repeat=7)))
import platform
print(platform.python_version())

On my system, I get:
0.719622326348
2.7.1


Benjamin Jessup

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Oct 4, 2012, 8:21:13 AM10/4/12
to pytho...@python.org

Steven D'Aprano

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Oct 4, 2012, 10:04:21 AM10/4/12
to
On Thu, 04 Oct 2012 08:21:13 -0400, Benjamin Jessup wrote:

> On 10/4/2012 12:20 AM, python-li...@python.org wrote:
>> How do you know that?
>>
>> No offence, but if you can't even work out whether lookups in a dict or
>> a list are faster, I can't imagine why you think you can intuit what
>> the fastest way to retrieve the nearest neighbours would be.
>
> Whats wrong with the test below?
[snip code]


I don't know. Is this a trick question? Is the answer, "nothing is wrong"?

It doesn't seem to be very useful code, but since I don't know what you
think you are testing, I can't tell you whether you are doing it wrong or
not.



--
Steven
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