我已经把这个作为一个课程的练习:打开文件，找到并替换字符串，并写入一个新文件。

class Letter:

    def __init__(self):

        with open("./Input/Names/invited_names.txt", "r") as file:
            # read the list of names
            list_names = [line.rstrip() for line in file]
            with open("./Input/Letters/starting_letter.docx", "r") as f:
                # read letter
                file_source = f.read()
            for name in list_names:
                with open(f"./Output/ReadyToSend/LetterTo{name}.docx", "w") as f:
                    # replace [name] with name of the list in the file
                    replace_string = file_source.replace('[name]', name)
                    # write to a new file
                    f.write(replace_string)


brief = Letter()

使用re.subn可以对替换过程进行更多的控制，例如将单词分成两行，区分大小写的匹配。此外，它返回匹配的数量，如果没有找到字符串，可以使用这些匹配来避免浪费资源。

import re

file = # path to file

# they can be also raw string and regex
textToSearch = r'Ha.*O' # here an example with a regex
textToReplace = 'hallo'

# read and replace
with open(file, 'r') as fd:
    # sample case-insensitive find-and-replace
    text, counter = re.subn(textToSearch, textToReplace, fd.read(), re.I)

# check if there is at least a  match
if counter > 0:
    # edit the file
    with open(file, 'w') as fd:
        fd.write(text)

# summary result
print(f'{counter} occurence of "{textToSearch}" were replaced with "{textToReplace}".')

一些正则表达式:

添加re.I标志，re.IGNORECASE的缩写形式，用于不区分大小写的匹配 对于多行替换re.subn(r'\n*'.join(textToSearch)， textToReplace, fd.read()))，取决于数据也'\n{，1}'。注意，在这种情况下，textToSearch必须是纯字符串，而不是正则表达式!

Fileinput已经支持就地编辑。在这种情况下，它将stdout重定向到文件:

#!/usr/bin/env python3
import fileinput

with fileinput.FileInput(filename, inplace=True, backup='.bak') as file:
    for line in file:
        print(line.replace(text_to_search, replacement_text), end='')

以读模式打开文件。以字符串格式读取文件。替换文本。关闭文件。再次以写模式打开文件。最后，将替换后的文本写入相同的文件。

try:
    with open("file_name", "r+") as text_file:
        texts = text_file.read()
        texts = texts.replace("to_replace", "replace_string")
    with open(file_name, "w") as text_file:
        text_file.write(texts)
except FileNotFoundError as f:
    print("Could not find the file you are trying to read.")

我也有同样的问题。问题是，当你在变量中加载一个.txt时，你把它当作一个字符串数组使用，而它是一个字符数组。

swapString = []
with open(filepath) as f: 
    s = f.read()
for each in s:
    swapString.append(str(each).replace('this','that'))
s = swapString
print(s)

您的问题源于读取和写入同一个文件。与其打开fileToSearch进行写入，不如打开一个实际的临时文件，然后在您完成并关闭tempFile之后，使用os。rename将新文件移动到fileToSearch上。