timeit模組
timeit模組可以用來測試一小段Python程式碼的執行速度。

class timeit.Timer(stmt=‘pass’, setup=‘pass’, timer=)
Timer是測量小段程式碼執行速度的類。

stmt引數是要測試的程式碼語句（statment）；

setup引數是執行程式碼時需要的設定；

timer引數是一個定時器函式，與平臺有關。

timeit.Timer.timeit(number=1000000)
Timer類中測試語句執行速度的物件方法。number引數是測試程式碼時的測試次數，預設為1000000次。方法返回執行程式碼的耗時，一個float型別的秒數。

list的操作測試
def t1():
l = []
for i in range(1000):
l = l + [i]
def t2():
l = []
for i in range(1000):
l.append(i)
def t3():
l = [i for i in range(1000)]
def t4():
l = list(range(1000))

from timeit import Timer

timer1 = Timer(“t1()”, “from main import t1”)
print("concat ",timer1.timeit(number=1000), “seconds”)
timer2 = Timer(“t2()”, “from main import t2”)
print("append ",timer2.timeit(number=1000), “seconds”)
timer3 = Timer(“t3()”, “from main import t3”)
print("comprehension ",timer3.timeit(number=1000), “seconds”)
timer4 = Timer(“t4()”, “from main

('concat ', 1.7890608310699463, ‘seconds’)

('append ', 0.13796091079711914, ‘seconds’)

('comprehension ', 0.05671119689941406, ‘seconds’)

('list range ', 0.014147043228149414, ‘seconds’)

insert與append比較

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

def t5():
li = []
for i in range(10000):
li.insert(0, i)

timer2 = Timer(‘t2()’, ‘from main import t2’)
print(“append:”, timer2.timeit(number=1000))

timer5 = Timer(‘t5()’, ‘from main import t5’)
print(“insert:”, timer5.timeit(number=1000))

append: 0.9202240769991477

insert: 21.039387496999552

從結果可以看出，append從尾端新增元素效率遠遠高於insert從頂端新增元素