測試一行代碼的運作時間,在Python中比較友善,可以直接使用timeit:
Timer 類:
__init__(stmt="pass", setup="pass", timer=default_timer)
stmt 是執行語句,setup 是導入執行語句環境
print_exc(file=None)
timeit(number=default_number)
傳回測試所用秒數,number 是每個測試中調用被計時語句的次數
repeat(repeat=default_repeat, number=default_number)
傳回測試所用秒數清單,repeat 是重複整個測試的次數,number 是每個測試中執行語句的次數
快捷方法:
timeit(stmt="pass", setup="pass", timer=default_timer, number=default_number)
= Timer(stmt, setup, timer).timeit(number)
repeat(stmt="pass", setup="pass", timer=default_timer, repeat=default_repeat, number=default_number)
= Timer(stmt, setup, timer).repeat(repeat, number)
default_timer 在 win32 下是 time.clock(),在 linux 下是 time.time()
default_number = 1000000
default_repeat = 3
執行個體:
import timeit
def func1(x):
pow(x, 2)
def func2(x):
return x * x
v = 10000
func1_test = 'func1(' + str(v) + ')'
func2_test = 'func2(' + str(v) + ')'
print timeit.timeit(func1_test, 'from __main__ import func1')
print timeit.timeit(func2_test, 'from __main__ import func2')
print timeit.repeat(func1_test, 'from __main__ import func1')
print timeit.repeat(func2_test, 'from __main__ import func2')
執行個體2:
#! /usr/bin/env python
# -*- coding: u8 -*-
import random
import timeit
def randDiff( k,n ):
'産生k個不相等的從1到n的随機數'
p = []
y1 = [random.randrange(1,n+1) for i in range(n)]
y2 = []
y2.extend(y1)
y1.sort()
for j in range(k):
temp1 = y1[j]
temp2 = y2.index(temp1)
p.append(temp2 + 1)
y2[temp2] = -1
return p
def randDif(k,n):
'新函數,生成k個1到n之間不相等的随機數'
if k>n:
return []
a = range(1,n+1)
random.shuffle(a)
return a[:k]
if __name__=='__main__':
print timeit.repeat("randDiff(3, 10)", "from __main__ import randDiff", timeit.default_timer, 3, 10000)
print timeit.repeat("randDif(3, 10)", "from __main__ import randDif", timeit.default_timer, 3, 10000)
看個例子吧
[python]
view plain
copy
1. >>> import timeit
2. #執行指令
3. >>> t2 = timeit.Timer('x=range(1000)')
4. #顯示時間
5. >>> t2.timeit()
6. 10.620039563513103
7.
8. #執行指令
9. >>> t1 = timeit.Timer('sum(x)', 'x = (i for i in range(1000))')
10. #顯示時間
11. >>> t1.timeit()
12. 0.1881566039438201
或者如下使用
[python] view plain copy
>>> import timeit
#執行指令
>>> t2 = timeit.Timer('x=range(1000)')
#顯示時間
>>> t2.timeit()
10.620039563513103
#執行指令
>>> t1 = timeit.Timer('sum(x)', 'x = (i for i in range(1000))')
#顯示時間
>>> t1.timeit()
0.1881566039438201
其實在ipython中可以直接使用
[python] view plain copy
In [1]: from timeit import timeit as timeit
In [2]: timeit('x=1')
Out[2]: 0.03820111778328037
In [3]: timeit('x=map(lambda x:x*10,range(32))')
Out[3]: 8.05639690328919