資料結構與演算法（二）

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python內建類型效能分析

timeit模組

class timeit.Timer(stmt="pass",setup=‘pass‘,time=<timer function>)

Timer是測量小段代碼執行速度的類

stmt參數是要測試的代碼語句（statment）

setup參數是運行代碼是需要的設定

timer 參數是一個定時器函數，與平台無關。

 

timeit.Timer.timeit(number=1000000)

Timer類中測試語句執行速度的對象方法，number參數是測量代碼時的測試冊數，預設為1000000次。方法返回執行代碼的平均耗時，一個float類型的秒數。

 

 

def t1():
li = []
for i in range(10000):
li.append(i)

def t2():
li = []
for i in range(10000):
li += [i]

def t3():
li = [i for i in range(10000)]

def t4():
li = list(range(10000))

def t5():
li = []
for i in range(10000):
li.extend([i])

timer1 = timeit("t1()","from __main__ import t1",number=1000)
print("append:",timer1)

timer2 = timeit("t2()","from __main__ import t2",number=1000)
print("+:",timer2)

timer3 = timeit("t3()","from __main__ import t3",number=1000)
print("i for i in range(n):",timer3)

timer4 = timeit("t4()","from __main__ import t4",number=1000)
print("list(range(n)):",timer4)

timer5 = timeit("t5()","from __main__ import t5",number=1000)
print("li.extend([i]):",timer5)

 

資料結構與演算法（二）