python中的数据提取

Question

```python

import csv
with open("C:/Users/film/gz.csv",'r') as csvfile:
reader = csv.reader(csvfile)
column = [row[5] for row in reader]
reader2 = csv.reader(csvfile)
column2=[row[10]for row in reader2]
print (column2)

```我想问问，为啥执行一个就可以，两个一起执行就不行，我想要提取表中的两列里面的数据，那位可以看看啊

Answer 1

因为文件里有一个类似于游标的概念，读取完文件文件之后就到了文件的末尾，再读取就没有内容了
你可以分每次读取都重新打开一次文件，

import csv
with open("C:/Users/film/gz.csv",'r') as csvfile:
    reader = csv.reader(csvfile)
    column = [row[5] for row in reader]
with open("C:/Users/film/gz.csv",'r') as csvfile:
    reader2 = csv.reader(csvfile)
    column2=[row[10]for row in reader2]

也可以打开一次文件，把需要的内容都读取到，然后再分离

import csv
with open("C:/Users/film/gz.csv",'r') as csvfile:
    reader = csv.reader(csvfile)
    d= [(row[5],row[10]) for row in reader]

column  = [i[0] for i in d]
column2  = [i[1] for i in d]