我如何使用timeit来比较我自己的函数(如“insertion_sort”和“tim_sort”)的性能?
当前回答
import timeit
def oct(x):
return x*x
timeit.Timer("for x in range(100): oct(x)", "gc.enable()").timeit()
其他回答
# Генерация целых чисел
def gen_prime(x):
multiples = []
results = []
for i in range(2, x+1):
if i not in multiples:
results.append(i)
for j in range(i*i, x+1, i):
multiples.append(j)
return results
import timeit
# Засекаем время
start_time = timeit.default_timer()
gen_prime(3000)
print(timeit.default_timer() - start_time)
# start_time = timeit.default_timer()
# gen_prime(1001)
# print(timeit.default_timer() - start_time)
如果你想快速比较两个代码/函数块,你可以这样做:
import timeit
start_time = timeit.default_timer()
func1()
print(timeit.default_timer() - start_time)
start_time = timeit.default_timer()
func2()
print(timeit.default_timer() - start_time)
如果你想在交互式Python会话中使用timeit,有两个方便的选项:
Use the IPython shell. It features the convenient %timeit special function: In [1]: def f(x): ...: return x*x ...: In [2]: %timeit for x in range(100): f(x) 100000 loops, best of 3: 20.3 us per loop In a standard Python interpreter, you can access functions and other names you defined earlier during the interactive session by importing them from __main__ in the setup statement: >>> def f(x): ... return x * x ... >>> import timeit >>> timeit.repeat("for x in range(100): f(x)", "from __main__ import f", number=100000) [2.0640320777893066, 2.0876040458679199, 2.0520210266113281]
如何使用带有接受参数的函数的Python REPL解释器的示例。
>>> import timeit
>>> def naive_func(x):
... a = 0
... for i in range(a):
... a += i
... return a
>>> def wrapper(func, *args, **kwargs):
... def wrapper():
... return func(*args, **kwargs)
... return wrapper
>>> wrapped = wrapper(naive_func, 1_000)
>>> timeit.timeit(wrapped, number=1_000_000)
0.4458435332577161
内置的timeit模块在IPython命令行中工作得最好。
为模块内的函数计时:
from timeit import default_timer as timer
import sys
def timefunc(func, *args, **kwargs):
"""Time a function.
args:
iterations=3
Usage example:
timeit(myfunc, 1, b=2)
"""
try:
iterations = kwargs.pop('iterations')
except KeyError:
iterations = 3
elapsed = sys.maxsize
for _ in range(iterations):
start = timer()
result = func(*args, **kwargs)
elapsed = min(timer() - start, elapsed)
print(('Best of {} {}(): {:.9f}'.format(iterations, func.__name__, elapsed)))
return result
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