python - 如果文件已经存在，如何防止 shutil.move 覆盖该文件？

Question

我在 Windows 中使用此 Python 代码:

shutil.move(documents_dir + "\\" + file_name, documents_dir + "\\backup\\"
            + subdir_name + "\\" + file_name)

当此代码被多次调用时，它会覆盖目标文件。我想移动文件如果目的地已经存在，则重命名它

例如文件名 = foo.pdf

在 backup 文件夹中将是 foo.pdf, foo(1).pdf, foo(2).pdf 等或类似的，例如带破折号foo-1.pdf, foo-2.pdf 等

Answer 1

您可以边走边检查 os.path.exists()。

import os
import shutil

file_name = 'test.csv'
documents_dir = r'C:\BR\Test'
subdir_name = 'test'

# using os.path.join() makes your code easier to port to another OS
source = os.path.join(documents_dir, file_name)
dest = os.path.join(documents_dir, 'backup', subdir_name, file_name)

num = 0
# loop until we find a file that doesn't exist
while os.path.exists(dest):
    num += 1

    # use rfind to find your file extension if there is one
    period = file_name.rfind('.')
    # this ensures that it will work with files without extensions
    if period == -1:
        period = len(file_name)

    # create our new destination
    # we could extract the number and increment it
    # but this allows us to fill in the gaps if there are any
    # it has the added benefit of avoiding errors 
    # in file names like this "test(sometext).pdf"
    new_file = f'{file_name[:period]}({num}){file_name[period:]}'

    dest = os.path.join(documents_dir, 'backup', subdir_name, new_file)

shutil.move(source, dest)

或者由于这可能在循环中使用，您可以将其放入函数中。

import os
import shutil

def get_next_file(file_name, dest_dir):
    dest = os.path.join(dest_dir, file_name)
    num = 0

    while os.path.exists(dest):
        num += 1

        period = file_name.rfind('.')
        if period == -1:
            period = len(file_name)

        new_file = f'{file_name[:period]}({num}){file_name[period:]}'

        dest = os.path.join(dest_dir, new_file)

    return dest

file_name = 'test.csv'
documents_dir = r'C:\BR\Test'
subdir_name = 'test'

source = os.path.join(documents_dir, file_name)

dest = get_next_file(file_name, os.path.join(documents_dir, 'backup', subdir_name))

shutil.move(source, dest)