Question

def Delete_con():
    contact_to_delete= input("choose name to delete from contact")
    to_Delete=list(contact_to_delete)
    with open("phonebook1.txt", "r+") as file:
        content = file.read()
        for line in content:
            if not any(line in line for line in to_Delete):
                content.write(line)

我得到零错误。但该行未删除。此功能询问用户他或她想要从文本文件中删除的名称。

Answer 1

这应该有所帮助。

def Delete_con():
    contact_to_delete= input("choose name to delete from contact")
    contact_to_delete = contact_to_delete.lower()   #Convert input to lower case
    with open("phonebook1.txt", "r") as file:
        content = file.readlines()              #Read lines from text
        content = [line for line in content if contact_to_delete not in line.lower()]   #Check if user input is in line 
    with open("phonebook1.txt", "w") as file:    #Write back content to text 
        file.writelines(content)

Answer 2

假设：

您希望用户只提供名称，而不是完整的“name：number”对
您的电话簿存储一个名称：每行数字对

我会做这样的事情：

import os
from tempfile import NamedTemporaryFile


def delete_contact():
    contact_name = input('Choose name to delete: ')
    # You probably want to pass path in as an argument
    path = 'phonebook1.txt'
    base_dir = os.path.dirname(path)
    with open(path) as phonebook, \
            NamedTemporaryFile(mode='w+', dir=base_dir, delete=False) as tmp:
        for line in phonebook:
            # rsplit instead of split supports names containing ':'
            # if numbers can also contain ':' you need something smarter
            name, number = line.rsplit(':', 1)
            if name != contact_name:
                tmp.write(line)
        os.replace(tmp.name, path)

使用这样的临时文件意味着如果在处理文件时出现问题，您没有留下半写的电话簿，您仍然可以保持原始文件不变。你也没有用这种方法将整个文件读入内存。

os.replace()仅适用于Python 3.3+，如果您使用的是旧版本，只要您不使用Windows，就可以使用os.rename()。

Here's the tempfile documentation。在这种情况下，您可以将NamedTemporaryFile(mode='w+', dir=base_dir, delete=False)视为open('tmpfile.txt', mode='w+')之类的内容。 NamedTemporaryFile使您不必为临时文件找到唯一的名称（这样您就不会覆盖现有文件）。 dir参数在与phonebook1.txt相同的目录中创建临时文件，这是一个好主意，因为os.replace()在跨两个不同的文件系统操作时可能会失败。

从python中的文本文件中删除用户定义的文本

2 个答案: