Besides the answers already mentioned, here is an explanation of why you have some random characters at the end: You are opening the file in r+ mode, not w mode. The key difference is that w mode clears the contents of the file as soon as you open it, whereas r+ doesn't. This means that if your file content is "123456789" and you write "www" to it, you get "www456789". It overwrites the characters with the new input, but leaves any remaining input untouched. You can clear a section of the file contents by using truncate(<startPosition>), but you are probably best off saving the updated file content to a string first, then doing truncate(0) and writing it all at once. Or you can use my library :D

你可以这样做替换

f1 = open('file1.txt', 'r')
f2 = open('file2.txt', 'w')
for line in f1:
    f2.write(line.replace('old_text', 'new_text'))
f1.close()
f2.close()

正如michaelb958所指出的，不能用不同长度的数据替换现有的部分，因为这会使其余部分不合适。我不同意其他人建议你从一个文件读到另一个文件。相反，我将把文件读入内存，修复数据，然后在单独的步骤中将其写入相同的文件。

# Read in the file
with open('file.txt', 'r') as file :
  filedata = file.read()

# Replace the target string
filedata = filedata.replace('abcd', 'ram')

# Write the file out again
with open('file.txt', 'w') as file:
  file.write(filedata)

除非你有一个巨大的文件要处理，它太大了，无法一次性加载到内存中，或者你担心如果在向文件写入数据的第二步过程中中断，可能会导致数据丢失。

(pip install python-util)

from pyutil import filereplace

filereplace("somefile.txt","abcd","ram")

将所有出现的“abcd”替换为“ram”。 该函数还通过指定regex=True来支持regex

from pyutil import filereplace

filereplace("somefile.txt","\\w+","ram",regex=True)

免责声明:我是作者(https://github.com/MisterL2/python-util)

def findReplace(find, replace):

    import os 

    src = os.path.join(os.getcwd(), os.pardir) 

    for path, dirs, files in os.walk(os.path.abspath(src)):

        for name in files: 

            if name.endswith('.py'): 

                filepath = os.path.join(path, name)

                with open(filepath) as f: 

                    s = f.read()

                s = s.replace(find, replace) 

                with open(filepath, "w") as f:

                    f.write(s) 

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)