python怎么在csv中写入

import pandas as pd

#任意的多组列表

a = [1,2,3]

b = [4,5,6]   

#字典中的key值即为csv中列名

dataframe = pd.DataFrame({'a_name':a,'b_name':b})

#将DataFrame存储为csv,index表示是否显示行名，default=True

dataframe.to_csv("test.csv",index=False,sep=',')

  a_name  b_name

0   1     4

1   2     5

2   3     6

import pandas as pd

data = pd.read_csv('test.csv')

import csv

#python2可以用file替代open

with open("test.csv","w") as csvfile:

    writer = csv.writer(csvfile)

    #先写入columns_name

    writer.writerow(["index","a_name","b_name"])

    #写入多行用writerows

    writer.writerows([[0,1,3],[1,2,3],[2,3,4]])

index  a_name  b_name

0      1      3

1      2      3

2      3      4

import csv

with open("test.csv","r") as csvfile:

    reader = csv.reader(csvfile)

    #这里不需要readlines

    for line in reader:

        print line