this is my implementation: ``` units = {"auto": -1, "s": 1, "ms": 1e3, "μs": 1e6, "ns": 1e9} def timef(unit="auto", number=1, garcol=True, get_time=False): """A decorator to measure the execution time of a function

Returns the return of the tested function if get_time is False or the execution time in unit if not

unit: one of "ns" (nanoseconds), "μs" (microseconds), "ms" (milliseconds), "s" (seconds) and "auto": (automatic) (default: "auto") garcol: if True enables garbage collection (default: True) get_time: if true return the execution time of the function (default: False) """ fun = False if callable(unit): fun = True func = unit unit = "auto" elif unit not in units: raise ValueError( "valid options: " "s(seconds), " "ms(milliseconds), " "μs(microseconds), " "ns(nanoseconds) " "and auto(automatic: default)")

def decorating_function(func): return _wrapper(func, number, units, unit, units[unit], garcol, get_time) return decorating_function(func) if fun else decorating_function

def _wrapper(func, number, units, unit, factor, garcol, get_time): def timed(*args, **kwargs): nonlocal unit, factor gcold = gc.isenabled() # disable garbage collection on demand if not garcol: gc.disable() try: if number > 0: start = default_timer() for _ in range(number): func(*args, **kwargs) time = default_timer() - start result = func(*args, **kwargs) finally: if gcold: gc.enable() if unit == "auto": for u, f in units.items(): if 1 <= int(time * f) < 1000: unit, factor = u, f break else: unit, factor = "s", 1 time *= factor print(f"{func.__qualname__}: {time:.4f} {unit}") return time if get_time else result return timed ``` it's not perfect but it works; you can control number of repetitions, garbage collection, unit ... and it produces a formatted output such as: `fun_to_time: 24.1056 ms`. ________________________________ De : Python-ideas python-ideas-bounces+amjadhedhili=outlook.com@python.org de la part de Steven D'Aprano steve@pearwood.info Envoyé : dimanche 7 octobre 2018 04:15 À : python-ideas@python.org Objet : Re: [Python-ideas] add a time decorator to timeit.py

On Sun, Oct 07, 2018 at 10:16:08AM +0000, Amjad Ben Hedhili wrote:

I think that a time decorator will be a useful addition to the sandard library, as i find the current way of measuring execution time a bit tedious:

timeit.timeit("fun_to_time(a, b)", setup="from __main__ import a, b", number=1)

There are lots of ways to call timeit, but generally if you are calling it with number=1 then your results may not be trustworthy. (That depends on the function, of course.) There's a reason why timeit defaults to number=1000000 rather than 1.

compared to:

@timef def fun_to_time(a, b): ...

The problem with that as an API is that once you have decorated the function to call timeit, how do you use it *without* calling timeit?

If you use functools.wraps, there will be a func_to_time.__wrapped__ but I don't think that calling that directly is a good interface.

or

timef(print)("Hello world!").

I already made a basic implementation of it, and it's working well.

Can you explain what the timef decorator does? What arguments does it take, how do we use it?

-- Steve _______________________________________________ Python-ideas mailing list Python-ideas@python.org https://mail.python.org/mailman/listinfo/python-ideas Code of Conduct: http://python.org/psf/codeofconduct/

On Sun, Oct 7, 2018 at 11:34 PM Steven D'Aprano steve@pearwood.info wrote:

Unfortunately, not every good idea can or will make it into the std lib. Even if the idea is good, we might decide that it belongs as a third- party library, or that the benefit is not enough to make up for the cost in effort or complexity. Or the idea is simply too controversial.

Or just too detaily. The given function has four keyword arguments that vary its behaviour slightly; if it gets into the stdlib, someone will ask for a way to control the output format, someone else will request that it be able to send to stderr instead of stdout, etc, etc, and suddenly the proposed function has two dozen kwargs. One of the powerful tools available to a programmer is having *your own* debug library, without having to worry about what other people would do that might be similar.

-0.5 on adding to the stdlib, -0 on putting on PyPI (I wouldn't bother looking on PyPI for something like this - I'd just write my own, specific to the need).

ChrisA

Summary: Python's timeit.timeit() has an undocumented feature / implementation detail that gives much of what the original poster has asked for. Perhaps revising the docs will solve the problem.

This thread has prompted me to look at timeit again. Usually, I look at the command line help first.

...

...

import timeit help(timeit)

Classes: Timer Functions: timeit(string, string) -> float repeat(string, string) -> list default_timer() -> float

This time, to my surprise, I found the following works:

...

...

def fn(): return 2 + 2 timeit.timeit(fn)

0.10153918000287376

Until today, as I recall, I didn't know this.

Now for: https://docs.python.org/3/library/timeit.html

I don't see any examples there, that show that timeit.timeit can take a callable as its first argument. So my ignorance can, I hope be forgiven.

Now for: https://github.com/python/cpython/blob/3.7/Lib/timeit.py#L100

This contains, for both the stmt and setup parameters, explicit tests such as

if isinstance(stmt, str): # string case elif callable(stmt): # callable case

So I think it's an undocumented feature, rather than an implementation detail.

And if you're a software historian, now perhaps look at https://github.com/python/cpython/commits/3.7/Lib/timeit.py

And also, if you wish, for the tests for timeit.py.

Summary: Python's timeit.timeit() has an undocumented feature / implementation detail that gives much of what the original poster has asked for. Perhaps revising the docs will solve the problem.

although timeit can be used with a callable, you need to create a lambda expression if the function has args: ``` def func_to_time(a, b): ...

timeit.timeit(lambda: func_to_time(a, b), globals=globals()) ``` and you can't use it as a decorator. ________________________________ De : Python-ideas python-ideas-bounces+amjadhedhili=outlook.com@python.org de la part de Jonathan Fine jfine2358@gmail.com Envoyé : dimanche 7 octobre 2018 09:15 À : python-ideas Objet : Re: [Python-ideas] add a time decorator to timeit.py

Summary: Python's timeit.timeit() has an undocumented feature / implementation detail that gives much of what the original poster has asked for. Perhaps revising the docs will solve the problem.

This thread has prompted me to look at timeit again. Usually, I look at the command line help first.

...

...

import timeit help(timeit)

Classes: Timer Functions: timeit(string, string) -> float repeat(string, string) -> list default_timer() -> float

This time, to my surprise, I found the following works:

...

...

def fn(): return 2 + 2 timeit.timeit(fn)

0.10153918000287376

Until today, as I recall, I didn't know this.

Now for: https://docs.python.org/3/library/timeit.html

I don't see any examples there, that show that timeit.timeit can take a callable as its first argument. So my ignorance can, I hope be forgiven.

Now for: https://github.com/python/cpython/blob/3.7/Lib/timeit.py#L100

This contains, for both the stmt and setup parameters, explicit tests such as

if isinstance(stmt, str): # string case elif callable(stmt): # callable case

So I think it's an undocumented feature, rather than an implementation detail.

And if you're a software historian, now perhaps look at https://github.com/python/cpython/commits/3.7/Lib/timeit.py

And also, if you wish, for the tests for timeit.py.

-- Jonathan _______________________________________________ Python-ideas mailing list Python-ideas@python.org https://mail.python.org/mailman/listinfo/python-ideas Code of Conduct: http://python.org/psf/codeofconduct/