timeit: Use thousands separators and print number of loops per second

[jstasiak]

BPO	18975
Nosy	@tim-one, @pitrou, @ezio-melotti, @bitdancer, @serhiy-storchaka, @jstasiak, @csabella
Files	timeit.patch timeit-v2.patch timeit-v3-actual-changes.patch timeit-v3-pep8.patch timeit-v3-actual-changes-no-separators.patch timeit-v4-actual-changes.patch

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

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GitHub fields:

assignee = None
closed_at = None
created_at = <Date 2013-09-08.16:00:31.283>
labels = ['type-feature', 'library']
title = 'timeit: Use thousands separators and print number of loops per second'
updated_at = <Date 2017-08-27.13:46:09.639>
user = 'https://github.com/jstasiak'

bugs.python.org fields:

activity = <Date 2017-08-27.13:46:09.639>
actor = 'cheryl.sabella'
assignee = 'none'
closed = False
closed_date = None
closer = None
components = ['Library (Lib)']
creation = <Date 2013-09-08.16:00:31.283>
creator = 'jstasiak'
dependencies = []
files = ['31672', '31673', '31683', '31684', '31786', '31792']
hgrepos = []
issue_num = 18975
keywords = ['patch']
message_count = 18.0
messages = ['197274', '197276', '197282', '197286', '197287', '197303', '197305', '197308', '197314', '197315', '197316', '197852', '197858', '197869', '197878', '197882', '197885', '300916']
nosy_count = 7.0
nosy_names = ['tim.peters', 'pitrou', 'ezio.melotti', 'r.david.murray', 'serhiy.storchaka', 'jstasiak', 'cheryl.sabella']
pr_nums = []
priority = 'normal'
resolution = None
stage = 'patch review'
status = 'open'
superseder = None
type = 'enhancement'
url = 'https://bugs.python.org/issue18975'
versions = ['Python 3.4']

[jstasiak]

This patch includes:

• making code more PEP-8-compatible and refactoring it a bit
• printing number of loops per second when using command line interface
• using thousands separators when printing numbers of loops (also in command line interface)
• changing examples in the module documentation

The output is changed from this:

10000 loops, best of 3: 40.3 usec per loop

to that:

10,000 loops, best of 3: 34.6 usec per loop, 28,870.783/s

I'm still not sure about details of "28,870.783/s" part:

• whether it should always include the fractional part (in this example it doesn't make any sense)
• maybe it should say "loops/s" rather than just "/s"

[jstasiak]

Oops, forgot to patch the tests, please find correct patch attached.

[ezio-melotti]

I personally dislike the "," as thousands separator, and if a separator is added at all I would prefer a space as defined in the SI standard0.

The PEP-8 changes should also me moved to a separate patch IMHO; the other changes are OK grouped together.

[jstasiak]

I agree with both notes. Splitting the patch won't be a problem.

As much as I don't fancy "," as thousands separator either - I just used what's in the standard library but I'll think about the best way of putting spaces there.

[pitrou]

I personally dislike the "," as thousands separator, and if a
separator is added at all I would prefer a space as defined in the SI
standard[0].

Then you really want a non-breaking space ;-)

(as a French person who's used to commas as decimal points, count me in the "commas as thousands separators are confusing" camp ;-))

• whether it should always include the fractional part (in this
  example it doesn't make any sense)

Indeed, it probably doesn't make sense unless the number is < 100.
I would also put that information inside parentheses, as it is redundant with the per-loop timing.

• maybe it should say "loops/s" rather than just "/s"

Yeah.

[serhiy-storchaka]

I'm afraid the adding any separators will make some people angry. With a comma or space it no more a valid number in Python and many other languages and can't be copy/pasted and parsed.

Actually I sometimes use small shell scripts to run "python -m timeit" and parsing results with grep, sed and awk. It is easer in simplest cases than writing it on Python (especially when different Python binaries used).

I'm -0,1.

[bitdancer]

I'm with Serhiy on this. So if separators are added, I would say they *must* be optional. Presumably if they are added they should be locale dependent :) All of which may well make it more complicated than it is worth.

[tim-one]

-1 from me, and I'm a comma-loving American ;-)

I'm sure lots of code in the wild parses this output - Serhiy isn't the only one doing it.

[jstasiak]

To me the point of this patch is adding number of loops per second information - using thousands separators was just an addition which I'm happy to drop.

Please find attached 2 patches:

• one containing actual changes - loops per second added, fractional part is printed when the number is less than 100, space is used as thousands separator; old part of the message is not affected
• one containing PEP-8 reformatting

So:

10000 loops, best of 3: 34.6 usec per loop (28 870 loops/s)

[pitrou]

So:

10000 loops, best of 3: 34.6 usec per loop (28 870 loops/s)

Looks fine to me (though having a decimal space at the right and not at
the left looks a bit weird).

[bitdancer]

I do not find a space to be an acceptable separator, sorry.

[jstasiak]

Antoine: I agree that it does look weird to have thousands separators at one place and not at the other but IMO it's still slightly better - the number formatted with separators is simply more readable that separator-less one.

R. David Murray: what's the acceptable separator then? Modifying it to be locale-aware would make it inconsistent with the rest of the output (which, admittedly, is also the case with introducing space separator, dot still is the fraction separator though).

I modified my patch to not have the separators at all, please find timeit-v3-actual-changes-no-separators.patch - if that's the condition for accepting this patch then so be it - the description of the patch would be "print number of loops per second" and the example output is:

10000 loops, best of 3: 34.6 usec per loop (28870 loops/s)

[bitdancer]

My vote is no separators. But I'm just one vote :)

[serhiy-storchaka]

My vote is no separators. But I'm just one vote :)

Seconded.

[pitrou]

I'm fine with the change too. Tim, what do you think?

Speaking of which, some examples were really done with an old machine:

    $ python -m timeit 'try:' '  str.__bool__' 'except AttributeError:' '  pass'
-   100000 loops, best of 3: 15.7 usec per loop
+   1000000 loops, best of 3: 0.701 usec per loop (1425528 loops/s)

:-)

[serhiy-storchaka]

Inconsistency: "sec per loop" vs. "loops/s".

[jstasiak]

That's right, I was actually wondering about it few minutes before you pointed it out. Find new patch attached.

[csabella]

Reviewing this patch, it appears that the PEP-8 changes to timeit.py are already in the source and the discussion of the thousands separator is no longer an issue with the underscore changes in 3.6 (meaning underscore now seems the way to separate digits in large numbers, although it seems the vote was to remove all separators from timeit anyway).

That would leave the loops per second request the only one still needed from this patch. But, with the subsequent change of selecting the time unit in timeit, perhaps this patch would need to be modified to print 'loops per {timeunit}'?