我想测量执行一个函数所花费的时间。我没时间工作:
import timeit
start = timeit.timeit()
print("hello")
end = timeit.timeit()
print(end - start)
我想测量执行一个函数所花费的时间。我没时间工作:
import timeit
start = timeit.timeit()
print("hello")
end = timeit.timeit()
print(end - start)
当前回答
下面是另一个用于计时代码的上下文管理器-
用法:
from benchmark import benchmark
with benchmark("Test 1+1"):
1+1
=>
Test 1+1 : 1.41e-06 seconds
或者,如果您需要时间值
with benchmark("Test 1+1") as b:
1+1
print(b.time)
=>
Test 1+1 : 7.05e-07 seconds
7.05233786763e-07
基准.py:
from timeit import default_timer as timer
class benchmark(object):
def __init__(self, msg, fmt="%0.3g"):
self.msg = msg
self.fmt = fmt
def __enter__(self):
self.start = timer()
return self
def __exit__(self, *args):
t = timer() - self.start
print(("%s : " + self.fmt + " seconds") % (self.msg, t))
self.time = t
改编自http://dabeaz.blogspot.fr/2010/02/context-manager-for-timing-benchmarks.html
其他回答
这种独特的基于类的方法提供了可打印的字符串表示、可自定义的舍入,以及以字符串或浮点形式方便地访问经过的时间。它是用Python 3.7开发的。
import datetime
import timeit
class Timer:
"""Measure time used."""
# Ref: https://stackoverflow.com/a/57931660/
def __init__(self, round_ndigits: int = 0):
self._round_ndigits = round_ndigits
self._start_time = timeit.default_timer()
def __call__(self) -> float:
return timeit.default_timer() - self._start_time
def __str__(self) -> str:
return str(datetime.timedelta(seconds=round(self(), self._round_ndigits)))
用法:
# Setup timer
>>> timer = Timer()
# Access as a string
>>> print(f'Time elapsed is {timer}.')
Time elapsed is 0:00:03.
>>> print(f'Time elapsed is {timer}.')
Time elapsed is 0:00:04.
# Access as a float
>>> timer()
6.841332235
>>> timer()
7.970274425
下面是一个返回“hh:mm:ss”字符串的小型计时器类:
class Timer:
def __init__(self):
self.start = time.time()
def restart(self):
self.start = time.time()
def get_time_hhmmss(self):
end = time.time()
m, s = divmod(end - self.start, 60)
h, m = divmod(m, 60)
time_str = "%02d:%02d:%02d" % (h, m, s)
return time_str
用法:
# Start timer
my_timer = Timer()
# ... do something
# Get time string:
time_hhmmss = my_timer.get_time_hhmmss()
print("Time elapsed: %s" % time_hhmmss )
# ... use the timer again
my_timer.restart()
# ... do something
# Get time:
time_hhmmss = my_timer.get_time_hhmmss()
# ... etc
我喜欢简单(python 3):
from timeit import timeit
timeit(lambda: print("hello"))
单个执行的输出为微秒:
2.430883963010274
说明:timeit默认执行匿名函数100万次,结果以秒为单位。因此,1次执行的结果相同,但平均以微秒为单位。
对于速度较慢的操作,添加较少的迭代次数,否则您可能会一直等待:
import time
timeit(lambda: time.sleep(1.5), number=1)
总迭代次数的输出始终以秒为单位:
1.5015795179999714
我参加聚会已经很晚了,但这种方法以前没有涉及过。当我们想要手动对某段代码进行基准测试时,我们可能需要首先找出哪些类方法占用了执行时间,这有时并不明显。我构建了以下元类来解决这个问题:
from __future__ import annotations
from functools import wraps
from time import time
from typing import Any, Callable, TypeVar, cast
F = TypeVar('F', bound=Callable[..., Any])
def timed_method(func: F, prefix: str | None = None) -> F:
prefix = (prefix + ' ') if prefix else ''
@wraps(func)
def inner(*args, **kwargs): # type: ignore
start = time()
try:
ret = func(*args, **kwargs)
except BaseException:
print(f'[ERROR] {prefix}{func.__qualname__}: {time() - start}')
raise
print(f'{prefix}{func.__qualname__}: {time() - start}')
return ret
return cast(F, inner)
class TimedClass(type):
def __new__(
cls: type[TimedClass],
name: str,
bases: tuple[type[type], ...],
attrs: dict[str, Any],
**kwargs: Any,
) -> TimedClass:
for name, attr in attrs.items():
if isinstance(attr, (classmethod, staticmethod)):
attrs[name] = type(attr)(timed_method(attr.__func__))
elif isinstance(attr, property):
attrs[name] = property(
timed_method(attr.fget, 'get') if attr.fget is not None else None,
timed_method(attr.fset, 'set') if attr.fset is not None else None,
timed_method(attr.fdel, 'del') if attr.fdel is not None else None,
)
elif callable(attr):
attrs[name] = timed_method(attr)
return super().__new__(cls, name, bases, attrs)
它允许如下使用:
class MyClass(metaclass=TimedClass):
def foo(self):
print('foo')
@classmethod
def bar(cls):
print('bar')
@staticmethod
def baz():
print('baz')
@property
def prop(self):
print('prop')
@prop.setter
def prop(self, v):
print('fset')
@prop.deleter
def prop(self):
print('fdel')
c = MyClass()
c.foo()
c.bar()
c.baz()
c.prop
c.prop = 2
del c.prop
MyClass.bar()
MyClass.baz()
它打印:
foo
MyClass.foo: 1.621246337890625e-05
bar
MyClass.bar: 4.5299530029296875e-06
baz
MyClass.baz: 4.291534423828125e-06
prop
get MyClass.prop: 3.814697265625e-06
fset
set MyClass.prop: 3.5762786865234375e-06
fdel
del MyClass.prop: 3.5762786865234375e-06
bar
MyClass.bar: 3.814697265625e-06
baz
MyClass.baz: 4.0531158447265625e-06
它可以与其他答案相结合,以更精确的方式代替time.time。
计算操作持续时间的最简单方法:
import time
start_time = time.monotonic()
<operations, programs>
print('seconds: ', time.monotonic() - start_time)
这里有官方文件。