python写入csv文件的几种方法总结

生成test.csv文件

#coding=utf-8
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=',')

内容为

   a_name  b_name
0       1       4
1       2       5
2       3       6

读取csv文件

#coding=utf-8
import pandas as pd
data = pd.read_csv('test.csv')
print(data)

输出

C:UsersmacnameDesktop	>python test.py
   a_name  b_name
0       1       4
1       2       5
2       3       6

---

另一种方法用csv包，一行一行写入

#coding=utf-8
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
    #写入多行用writerows
    writer.writerows([["index","a_name","b_name"],[0,1,3],[1,2,3],[2,3,4]])

内容为

index,a_name,b_name

0,1,3

1,2,3

2,3,4

读取csv文件用reader

#coding=utf-8
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)

输出

C:UsersmacnameDesktop	>python test.py
['index', 'a_name', 'b_name']
[]
['0', '1', '3']
[]
['1', '2', '3']
[]
['2', '3', '4']
[]