如何搜索和替换文件中的文本?

如何使用python3搜索和替换文件中的文本?

这是我的代码:

import os
import sys
import fileinput

print ("Text to search for:")
textToSearch = input( "> " )

print ("Text to replace it with:")
textToReplace = input( "> " )

print ("File to perform Search-Replace on:")
fileToSearch  = input( "> " )
#fileToSearch = 'D:\dummy1.txt'

tempFile = open( fileToSearch, 'r+' )

for line in fileinput.input( fileToSearch ):
    if textToSearch in line :
        print('Match Found')
    else:
        print('Match Not Found!!')
    tempFile.write( line.replace( textToSearch, textToReplace ) )
tempFile.close()


input( '\n\n Press Enter to exit...' )

输入文件:

hi this is abcd hi this is abcd
This is dummy text file.
This is how search and replace works abcd

当我在上面的输入文件中搜索并将“ram”替换为“abcd”时，它就像一个咒语。但当我反过来做，即替换'abcd'由'ram'，一些垃圾字符被留在最后。

将'abcd'替换为'ram'

hi this is ram hi this is ram
This is dummy text file.
This is how search and replace works rambcd

当前回答

我稍微修改了Jayram Singh的帖子，以替换每一个'!'字符转换为一个数字，我想在每个实例中增加这个数字。我想这对那些想要修改每行出现不止一次的字符并且想要迭代的人可能会有帮助。希望这能帮助到别人。PS-我在编码方面很新，所以如果我的帖子在任何方面都不合适，我很抱歉，但这对我来说是有效的。

f1 = open('file1.txt', 'r')
f2 = open('file2.txt', 'w')
n = 1  

# if word=='!'replace w/ [n] & increment n; else append same word to     
# file2

for line in f1:
    for word in line:
        if word == '!':
            f2.write(word.replace('!', f'[{n}]'))
            n += 1
        else:
            f2.write(word)
f1.close()
f2.close()

2017-09-24 16:57:20

其他回答

正如Jack Aidley发布的和J.F. Sebastian指出的那样，这个代码是行不通的:

 # Read in the file
filedata = None
with file = open('file.txt', 'r') :
  filedata = file.read()

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

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

但这段代码将工作(我已经测试过了):

f = open(filein,'r')
filedata = f.read()
f.close()

newdata = filedata.replace("old data","new data")

f = open(fileout,'w')
f.write(newdata)
f.close()

使用此方法，fileein和fileout可以是同一个文件，因为Python 3.3将在打开进行写入时覆盖该文件。

2014-04-05 05:19:15

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。

2013-06-17 05:43:36

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()

2013-06-17 05:32:29

我是这样做的:

#!/usr/bin/env python3

import fileinput
import os

Dir = input ("Source directory: ")
os.chdir(Dir)

Filelist = os.listdir()
print('File list: ',Filelist)

NomeFile = input ("Insert file name: ")

CarOr = input ("Text to search: ")

CarNew = input ("New text: ")

with fileinput.FileInput(NomeFile, inplace=True, backup='.bak') as file:
    for line in file:
        print(line.replace(CarOr, CarNew), end='')

file.close ()

2017-02-16 21:26:18

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

2020-12-15 01:18:22

如何搜索和替换文件中的文本?

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