[program-l] Re: Python list access speeds
- From: "R Dinger" <rrdinger@xxxxxxxxxx>
- To: <program-l@xxxxxxxxxxxxx>
- Date: Mon, 1 Oct 2012 19:26:35 -0700
Here is how to do short timing tests using the timeit module from the
command line on windows. (C> is the prompt.
C> python -m timeit -s "import random" random.randint(1, 100)
or
C> python -m timeit -s "import random" int(1 + random.random()*99)
The above may be easier for short code fragments like the ones you were
looking at.
Richard
----- Original Message -----
From: "Jacob Kruger" <jacob@xxxxxxxxxxxxx>
To: <program-l@xxxxxxxxxxxxx>
Sent: Monday, October 01, 2012 1:26 PM
Subject: [program-l] Re: Python list access speeds
Ok, you were right - just did something similar again, and difference was:
It took 0.167999982834 seconds to do randInt 100000 times
It took 0.0449998378754 seconds to do random and convert output 100000 times
Here's the code:
#start code
import random, time
tInt = time.time()
for I in range(1, 100000):
iRand = random.randint(1, 100)
print "It took " + str(time.time() - tInt) + " seconds to do randInt 100000
times"
tRand = time.time()
for I in range(1, 100000):
fRand = random.random()
iRand = int(fRand * 100)
print "It took " + str(time.time() - tRand) + " seconds to do random and
convert output 100000 times"
#end code
Jacob Kruger
Blind Biker
Skype: BlindZA
'...fate had broken his body, but not his spirit...'
----- Original Message -----
From: "R Dinger" <rrdinger@xxxxxxxxxx>
To: <program-l@xxxxxxxxxxxxx>
Sent: Monday, October 01, 2012 4:42 PM
Subject: [program-l] Re: Python list access speeds
> Regarding your random tests: reducing time from 7 seconds to 2.7 is still
> 2.59 times faster and that could be significant.
>
> I vaguely recall your test, but I thought it was much closer.
>
> Richard
> ----- Original Message -----
> From: "Jacob Kruger" <jacob@xxxxxxxxxxxxx>
> To: <program-l@xxxxxxxxxxxxx>
> Sent: Sunday, September 30, 2012 9:36 PM
> Subject: [program-l] Re: Python list access speeds
>
>
> Reminds me of a test I did - put together two loops where used either
> random.random() and converted the result to a number ranging from 1 to 100
> sort of manually, and then did the same loop, but using random.randint(1,
> 100), and got them to both operate like 100000 times, and it was actually
> slightly quicker to just use random.random(), but anyway - think
> difference
> was like 2.7 seconds, compared to like 7 seconds.
>
> Stay well
>
> Jacob Kruger
> Blind Biker
> Skype: BlindZA
> '...fate had broken his body, but not his spirit...'
>
> ----- Original Message -----
> From: "R Dinger" <rrdinger@xxxxxxxxxx>
> To: "programming" <program-l@xxxxxxxxxxxxx>
> Sent: Monday, October 01, 2012 1:01 AM
> Subject: [program-l] Python list access speeds
>
>
>>I got to thinking about list access speeds when reading replies to Al's
>> iterator reset question last week, so I decided to do some testing with
>> the
>> timeit module. I tested access by subscript and by direct iteration.
>>
>> I used the following setup code (a list of 500 random numbers) for all
>> the
>> tests. The time to execute the setup code is not included in the timing
>> tests.
>> setup = """
>> from random import random
>> valList = []
>> for i in xrange(500):
>> valList.append(random())
>> """
>>
>> The following code fragments were tested each running the loop 1 million
>> times.
>> stmt1 = """
>> for i in range(len(valList)):
>> v = valList[i]
>> """
>> time: 8.01 sec
>>
>> stmt2 = """
>> for i in xrange(len(valList)):
>> v = valList[i]
>> """
>> time: 7.43 sec
>>
>> stmt3 = """
>> for v in valList:
>> pass
>> """
>> time: 2.67 sec
>>
>> stmt4 = """
>> for i, v in enumerate(valList):
>> pass
>> """
>> time: 6.12 sec
>>
>> So access by subscripting from a list generated by the range function is
>> the
>> slowest. In the second test using xrange (a generator) helped a little,
>> but
>> not much. The third test using direct iteration of the list is clearly
>> much
>> faster. Finally in the last test I used the enumerate object to generate
>> the subscripts in case that was needed by the application in addition to
>> the
>> list value.
>>
>> The timeit module is quite handy, but be careful it can be quite
>> addictive
>> and lead to late nights testing all sorts of code fragments.
>>
>> Richard
>>
>> ** To leave the list, click on the immediately-following link:-
>> ** [mailto:program-l-request@xxxxxxxxxxxxx?subject=unsubscribe]
>> ** If this link doesn't work then send a message to:
>> ** program-l-request@xxxxxxxxxxxxx
>> ** and in the Subject line type
>> ** unsubscribe
>> ** For other list commands such as vacation mode, click on the
>> ** immediately-following link:-
>> ** [mailto:program-l-request@xxxxxxxxxxxxx?subject=faq]
>> ** or send a message, to
>> ** program-l-request@xxxxxxxxxxxxx with the Subject:- faq
>>
>
> ** To leave the list, click on the immediately-following link:-
> ** [mailto:program-l-request@xxxxxxxxxxxxx?subject=unsubscribe]
> ** If this link doesn't work then send a message to:
> ** program-l-request@xxxxxxxxxxxxx
> ** and in the Subject line type
> ** unsubscribe
> ** For other list commands such as vacation mode, click on the
> ** immediately-following link:-
> ** [mailto:program-l-request@xxxxxxxxxxxxx?subject=faq]
> ** or send a message, to
> ** program-l-request@xxxxxxxxxxxxx with the Subject:- faq
>
> ** To leave the list, click on the immediately-following link:-
> ** [mailto:program-l-request@xxxxxxxxxxxxx?subject=unsubscribe]
> ** If this link doesn't work then send a message to:
> ** program-l-request@xxxxxxxxxxxxx
> ** and in the Subject line type
> ** unsubscribe
> ** For other list commands such as vacation mode, click on the
> ** immediately-following link:-
> ** [mailto:program-l-request@xxxxxxxxxxxxx?subject=faq]
> ** or send a message, to
> ** program-l-request@xxxxxxxxxxxxx with the Subject:- faq
>
** To leave the list, click on the immediately-following link:-
** [mailto:program-l-request@xxxxxxxxxxxxx?subject=unsubscribe]
** If this link doesn't work then send a message to:
** program-l-request@xxxxxxxxxxxxx
** and in the Subject line type
** unsubscribe
** For other list commands such as vacation mode, click on the
** immediately-following link:-
** [mailto:program-l-request@xxxxxxxxxxxxx?subject=faq]
** or send a message, to
** program-l-request@xxxxxxxxxxxxx with the Subject:- faq
** To leave the list, click on the immediately-following link:-
** [mailto:program-l-request@xxxxxxxxxxxxx?subject=unsubscribe]
** If this link doesn't work then send a message to:
** program-l-request@xxxxxxxxxxxxx
** and in the Subject line type
** unsubscribe
** For other list commands such as vacation mode, click on the
** immediately-following link:-
** [mailto:program-l-request@xxxxxxxxxxxxx?subject=faq]
** or send a message, to
** program-l-request@xxxxxxxxxxxxx with the Subject:- faq
Other related posts:
