python写入csv文件的几种方法

python写入csv文件的几种方法

最常用的一种方法，利用pandas包

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=’,’)

运行结果

 同样pandas也提供简单的读csv方法，会得到一个DataFrame类型的data

import pandas as pd
data = pd.read_csv('test.csv')

另一种方法用csv包，一行一行写入

import csv

#python2可以用file替代open

with open(“test.csv”,“w”) as csvfile:

writer = csv.writer(csvfile)

</span><span style="color: #008000;">#</span><span style="color: #008000;">先写入columns_name</span>
writer.writerow([<span style="color: #800000;">"</span><span style="color: #800000;">index</span><span style="color: #800000;">"</span>,<span style="color: #800000;">"</span><span style="color: #800000;">a_name</span><span style="color: #800000;">"</span>,<span style="color: #800000;">"</span><span style="color: #800000;">b_name</span><span style="color: #800000;">"</span><span style="color: #000000;">])
</span><span style="color: #008000;">#</span><span style="color: #008000;">写入多行用writerows</span>
writer.writerows([[0,1,3],[1,2,3],[2,3,4]])</pre>

运行结果：

 读取csv文件用reader

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