正则表达式搜索使用Python替换目录中的多个文件

Question

Where am I going wrong ??

import os, os.path, re

path = "D:\python-test"
myfiles = os.listdir(path)

REGEXES = [(re.compile(r'dog'), 'cat'),
           (re.compile(r'123'), '789')]
for f in myfiles:

    file_name, file_extension = os.path.splitext(f)

    if file_extension in ('.txt', '.doc', '.odt', '.htm', '.html', '.java'):

        input_file = os.path.join(path, f)

        with open(input_file, "w") as fi:
            for line in fi:
                for search, replace in REGEXES:
                    line = search.sub(replace, line)
                fi.write(line)

Somehow its not working. I want to make the replacements in the current file and not a new file.

Update: How about creating A_reg.java from A.java. Moving A.java to a separate local folder and then renaming A_reg.java back to A.java . Possible ? If yes, please help me out with the code.

Answer 1

This is perfectly normal: you overwrite the files themselves. Write in new files, then rename.

Also, opening the way you do truncates files:

$ cat t.txt 
foo
$ python
>>> f = open("t.txt", "w")
>>> f.close()
>>> exit()
$ cat t.txt
# file is empty!!
$ 

Answer 2

Based on the inputs from Fge. I could make it work by using

from shutil import move

move(output_file, input_file)

Thus the working code will be

import os, os.path, re
from shutil import move

path = "D:\python-test"
myfiles = os.listdir(path)

REGEXES = [(re.compile(r'dog'), 'cat'),
           (re.compile(r'123'), '789')]
for f in myfiles:

file_name, file_extension = os.path.splitext(f)
generated_output_file = file_name + "_regex" + file_extension

if file_extension in ('.txt', '.doc', '.odt', '.htm', '.html', '.java'):

    input_file = os.path.join(path, f)
    output_file = os.path.join(path, generated_output_file)

    with open(input_file, "r") as fi, open(output_file, "w") as fo:
        for line in fi:
            for search, replace in REGEXES:
                line = search.sub(replace, line)
            fo.write(line)

move(output_file, input_file)