在 csv 文件中写入新行 [重复]

Posted 2023-02-23

【中文标题】在 csv 文件中写入新行 [重复]

【英文标题】：Writing new lines in a csvFile [duplicate]

【发布时间】：2018-11-28 15:14:57

【问题描述】：

我尝试创建一些代码来将新注册用户写入 csv 文件。它正在替换文件中的现有用户。现在它没有输入任何数据。我不确定我哪里出错了。

这是代码：

FirstName = input("Enter your  first name: ")
Surname = input("Enter your surname: ")
Age = input("Enter your age: ")
YearGroup = input("Enter your year group: ")
userName = input("Create a unique username: ")
passWord = input("Create a password: ")
fieldnames =['Username', 'Surname', 'First Name', 'Age', 'YearGroup', 'passWord']
reG = ['Username': userName, 'Surname': Surname, 'First Name': FirstName,
                    'Age': Age, 'YearGroup': YearGroup, 'passWord': passWord]
with open('StudentUserName.csv', 'w', newline='\n') as csvUser:
    reG = ['Username': userName, 'Surname': Surname, 'First Name': FirstName,
                    'Age': Age, 'YearGroup': YearGroup, 'passWord': passWord]
    writer = csv.DictWriter(csvUser, fieldnames)
    #writer.seek(0,2)
    writer.writeheader()
    writer.writerow(reG)

    #writer.writerow("\r")
    #writer.writerow(userName, Surname, FirstName,
    #                 Age, YearGroup, passWord)
csvUser.close()
print ("Registration completed")

【问题讨论】：

不会按需要运行：reG = 'Username': userName, 'Surname': Surname, First Name': FirstName, 'Age': Age, 'YearGroup': YearGroup, 'passWord': passWord

【参考方案1】：

这里有一些调整可以让您的程序按预期工作：

import csv
import os

FirstName = input("Enter your  first name: ")
Surname = input("Enter your surname: ")
Age = input("Enter your age: ")
YearGroup = input("Enter your year group: ")
userName = input("Create a unique username: ")
passWord = input("Create a password: ")

fieldnames = ['Username', 'Surname', 'First Name', 'Age', 'YearGroup', 'passWord']

filename = 'StudentUserName.csv'

# The file is now opened in append mode instead of write mode.
with open(filename, 'a', newline='\n') as csvUser:

    # reG is now a dictionary, as required by writerow.
    reG = 'Username': userName, 'Surname': Surname, 'First Name': FirstName,
           'Age': Age, 'YearGroup': YearGroup, 'passWord': passWord

    writer = csv.DictWriter(csvUser, fieldnames=fieldnames)

    # if it's an empty file, write the header
    if os.stat(filename).st_size == 0:
        writer.writeheader()

    writer.writerow(reG)

    # writer.writerow("\r")
    # writer.writerow(userName, Surname, FirstName,
    #                 Age, YearGroup, passWord)
csvUser.close()
print ("Registration completed")

文件现在以追加模式而不是写入模式打开。 reG 现在是字典，符合 writerow 的要求。 仅当文件为空时才添加标头。