Question

name = input("Enter a name : ")
fieldnames = ["first_name", "number"]
with open('names.csv') as csvfile, open('output.csv', 'w') as outputfile:
    reader = csv.DictReader(csvfile, fieldnames=fieldnames)
    writer = csv.DictWriter(outputfile, fieldnames=fieldnames)
    for line in reader:
        if name not in line:
            fieldnames = ["name", "number"]
            writer.writeheader()
            writer.writerow({'first_name': row['first_name'],
                             'number': row['number']})
with open('names.csv', 'w') as csvfile, open('output.csv') as outputfile:
    reader = csv.DictReader(outputfile, fieldnames=fieldnames)
    writer = csv.DictWriter(csvfile, fieldnames=fieldnames)
    for row in reader:
        fieldnames = ['first_name', 'number']
        writer.writeheader()
        writer.writerow({'first_name': row['first_name'],
                         'last_name': row['number']})

这是我迄今为止所编码的内容。我想将不包含name变量的行写入输出文件并将其写回csvfile（names.csv）

James Smith,2025550131
Kevin Harris,2025550105

这就是我的csvfile的样子。

first_name,last_name
James Smith,2025550131
first_name,last_name
James Smith,2025550131

这是运行代码后的names.csv文件。

Answer 1

row未在您的第一个写循环中声明，因此在IDE中运行此操作可能会记住半成功尝试的输出，并且您有一个奇怪的问题。

您每次都会写标题。不管怎样，默认情况下已经完成了。

另外：您需要与键进行比较，而不是与值进行比较。 if name not in row:检查名称是否为密钥，密钥不是"first_name",和"number"。

您需要if name != row['first_name']:

最后但并非最不重要的是，无需再次读取/写入文件来替换输入，只需执行shutil.move覆盖输出。

我的修正提案（注意newline=''，在使用python 3避免某些不是最新版本的空行时更好）：

import shutil,csv

name = input("Enter a name : ")
fieldnames = ["first_name", "number"]
with open('names.csv') as csvfile, open('output.csv', 'w',newline='') as outputfile:
    reader = csv.DictReader(csvfile, fieldnames=fieldnames)
    writer = csv.DictWriter(outputfile, fieldnames=fieldnames)
    for row in reader:   # row, not line !!
        if name != row['first_name']:
            writer.writerow({'first_name': row['first_name'], 'number': row['number']})

# replace original file
shutil.move('output.csv','names.csv')

Answer 2

您需要阅读输入name.csv文件。

签入名称与输入名称匹配，然后忽略该行。

如果不匹配，则将内容写入输出文件。

最后，只需将输出文件复制到原始的name.csv文件中。

import csv, shutil
name = 'vikash' # This you can take as input from user
fieldnames = ["first_name", "number"]
with open('names.csv', 'r') as csvfile, open('output.csv', 'w') as outputfile:
    reader = csv.DictReader(csvfile, fieldnames=fieldnames)
    writer = csv.DictWriter(outputfile, fieldnames=fieldnames)
    for row in reader:
        if not name == row['first_name']:
            writer.writerow({'first_name': row['first_name'], 'number': row['number']})
shutil.move('output.csv','names.csv')

names.csv

first_name,number
vikash,1
viki,2
pawan,3

output.csv

first_name,number
viki,2
pawan,3

您的代码无效的原因：

name = input("Enter a name : ")
fieldnames = ["first_name", "number"]
with open('names.csv') as csvfile, open('output.csv', 'w') as outputfile:
    reader = csv.DictReader(csvfile, fieldnames=fieldnames)
    writer = csv.DictWriter(outputfile, fieldnames=fieldnames)
    for line in reader:
        # you are reading line from reader but you are using row later.
        if name not in line:
            fieldnames = ["name", "number"]
            # above line is not needed as its already initialised earlier.
            writer.writeheader()
            # this is not required as header will be written automatically. 
            # Plus you also don't want to write header ever time you write a row to the output file.
            writer.writerow({'first_name': row['first_name'], 'number': row['number']})
            # use line variable here or change line above to row.

从csv文件中删除一行

2 个答案: