*****
## 代码执行时间测量模块
```
li = []
li.append()
li.insert()
```
### timeit模块
timeit模块可以用来测试一小段Python代码的执行速度。
```
class timeit.Timer(stmt='pass', setup='pass', timer=<timer function>)
Timer是测量小段代码执行速度的类。
stmt参数是要测试的代码语句（statment）；
setup参数是运行代码时需要的设置；
timer参数是一个定时器函数，与平台有关。
```
timeit.Timer.timeit(number=1000000)
Timer类中测试语句执行速度的对象方法。number参数是测试代码时的测试次数，默认为1000000次。方法返回执行代码的平均耗时，一个float类型的秒数。
### list的操作测试
```
def test1():
l = []
for i in range(1000):
l = l + [i]
def test2():
l = []
for i in range(1000):
l.append(i)
def test3():
l = [i for i in range(1000)]
def test4():
l = list(range(1000))
def test5():
li = []
for i in range(1000):
li.insert(0, i)
from timeit import Timer
t1 = Timer("test1()", "from __main__ import test1")
print("add", t1.timeit(number=1000))
t2 = Timer("test2()", "from __main__ import test2")
print("append ",t2.timeit(number=1000))
t3 = Timer("test3()", "from __main__ import test3")
print("list derivation",t3.timeit(number=1000))
t4 = Timer("test4()", "from __main__ import test4")
print("list range ",t4.timeit(number=1000))
t5 = Timer("test5()", "from __main__ import test5")
print("list insert ",t5.timeit(number=1000))
```
