在Python中追加csv文件

Question

嗨，我有一个csv文件，名称和姓氏以及空的用户名和密码列。 如何使用python csv写入每行的第3列和第4列，只需追加它，不会覆盖任何内容。

Answer 1

csv模块没有这样做，你必须将它写出到一个单独的文件，然后用新的文件覆盖旧文件，或者将整个文件读入内存，然后写上它。

我建议第一个选项：

from csv import writer as csvwriter, reader as cvsreader 
from os import rename # add ', remove' on Windows 

with open(infilename) as infile: 
    csvr = csvreader(infile) 
    with open(outfilename, 'wb') as outfile: 
     csvw = csvwriter(outfile) 
     for row in csvr: 
      # do whatever to get the username/password 
      # for this row here 
      row.append(username) 
      row.append(password) 
      csvw.writerow(row) 
      # or 'csvw.writerow(row + [username, password])' if you want one line 

# only on Windows 
# remove(infilename) 
rename(outfilename, infilename)