python读csv文件的优化

贴代码如下：

1. file=open("JData/JData_Action_201602.csv")
2. start=time.time()
3. for i in range(0,100):
4. j=csv.reader(file)
5. Time1=time.time()
6. Time1=Time1-start
7. start=time.time()
8. for i in range(0,100):
9. j=csv.reader(open("JData/JData_Action_201602.csv"))
10. Time2=time.time()
11. Time2=Time2-start
12. print "Time1:",Time1
13. print "Time2:",Time2

贴结果如下：

• lu@lu:~$ python dataCleaner.py
• Time1: 0.000128984451294
• Time2: 0.000988006591797
• lu@lu:~$ python dataCleaner.py
• Time1: 0.000130891799927
• Time2: 0.00102400779724
• lu@lu:~$ python dataCleaner.py
• Time1: 6.29425048828e-05
• Time2: 0.000524044036865
• lu@lu:~$ python dataCleaner.py
• Time1: 0.000155925750732
• Time2: 0.00112199783325
• lu@lu:~$ python dataCleaner.py
• Time1: 6.79492950439e-05
• Time2: 0.000508069992065

总结：

　　真正耗时的是读文件操作，因此建议先把文件读好，也就是生成Ｔｉｍｅ１的那种方式