python csv复制列
我有一个包含以下内容的文件
first_name,last_name,uid,email,dep_code,dep_name
john,smith,jsmith,jsmith@gmail.com,finance,21230
john,king,jking,jjing@gmail.com,human resource,31230
我想复制列“电子邮件”，并创建一个新的列“email2”，然后从列email2替换gmail.com到hotmail.com
我是python的新手，所以需要专家的帮助，我尝试了几个脚本，但是如果有更好的方法去做，那么请让我知道。 原始文件包含60000行。
with open('c:Python27scriptscolnewfile.csv', 'rb') as fp_in1, open('c:Python27scriptsfinal.csv', 'wb') as fp_out1:
writer1 = csv.writer(fp_out1, delimiter=",")
reader1 = csv.reader(fp_in1, delimiter=",")
domain = "@hotmail.com"
for row in reader1:
if row[2:3] == "uid":
writer1.append("Email2")
else:
writer1.writerow(row+[row[2:3]])
这里是最后一个脚本，唯一的问题是它没有完成整个outfile，它只显示61409行，而在输入文件中有61438行。
inFile ='c： Python27 scripts in-093013.csv'outFile ='c： Python27 scripts final.csv'
打开（outFile，'wb'）作为fp_out1：writer = csv.writer（fp_out1，delimiter =“，”）阅读器= csv.reader（fp_in1，delimiter =“，”）打开（inFile，'rb'）作为fp_in1， ）for col in reader：del col [6：] writer.writerow（col）headers = next（reader）writer.writerow（headers + ['email2']）用于阅读器中的行：if len（row）> 3：email = email.split（'@'，1）[0] +'@ hotmail.com'writer.writerow（row + [email]）
如果您在阅读器上打电话给next() ，您一次只能看到一行; 用它来复制标题。 复制电子邮件栏非常简单：
import csv
infilename = r'c:Python27scriptscolnewfile.csv'
outfilename = r'c:Python27scriptsfinal.csv'
with open(infilename, 'rb') as fp_in, open(outfilename, 'wb') as fp_out:
reader = csv.reader(fp_in, delimiter=",")
headers = next(reader) # read first row
writer = csv.writer(fp_out, delimiter=",")
writer.writerow(headers + ['email2'])
for row in reader:
if len(row) > 3:
# make sure there are at least 4 columns
email = row[3].split('@', 1)[0] + '@hotmail.com'
writer.writerow(row + [email])
此代码将第一个@符号上的电子邮件地址分开，接受拆分的第一部分并在其后添加@hotmail.com ：
>>> 'example@gmail.com'.split('@', 1)[0]
'example'
>>> 'example@gmail.com'.split('@', 1)[0] + '@hotmail.com'
'example@hotmail.com'
以上产生：
first_name,last_name,uid,email,dep_code,dep_name,email2
john,smith,jsmith,jsmith@gmail.com,finance,21230,jsmith@hotmail.com
john,king,jking,jjing@gmail.com,human resource,31230,jjing@hotmail.com
为您的示例输入。
这可以使用熊猫非常干净地完成。 这里是：
In [1]: import pandas as pd
In [3]: df = pd.read_csv('your_csv_file.csv')
In [4]: def rename_email(row):
...: return row.email.replace('gmail.com', 'hotmail.com')
...:
In [5]: df['email2'] = df.apply(rename_email, axis=1)
In [6]: """axis = 1 or ‘columns’: apply function to each row"""
In [7]: df
Out[7]:
first_name last_name uid email dep_code dep_name email2
0 john smith jsmith jsmith@gmail.com finance 21230 jsmith@hotmail.com
1 john king jking jjing@gmail.com human resource 31230 jjing@hotmail.com
In [8]: df.to_csv('new_update_email_file.csv')
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