python shutil.copytree_Python shutil copytree:使用ignore函数保留特定的文件类型

I'm trying to figure out how to copy CAD drawings (".dwg", ".dxf) from a source directory with subfolders to a destination directory and maintaining the original directory and subfolders structure.

Original Directory: H:\Tanzania...\Bagamoyo_Single_line.dwg

Source Directory: H:\CAD\Tanzania...\Bagamoyo_Single_line.dwg

I found the following answer from @martineau within the following post: Python Factory Function

from fnmatch import fnmatch, filter

from os.path import isdir, join

from shutil import copytree

def include_patterns(*patterns):

"""Factory function that can be used with copytree() ignore parameter.

Arguments define a sequence of glob-style patterns

that are used to specify what files to NOT ignore.

Creates and returns a function that determines this for each directory

in the file hierarchy rooted at the source directory when used with

shutil.copytree().

"""

def _ignore_patterns(path, names):

keep = set(name for pattern in patterns

for name in filter(names, pattern))

ignore = set(name for name in names

if name not in keep and not isdir(join(path, name)))

return ignore

return _ignore_patterns

# sample usage

copytree(src_directory, dst_directory,

ignore=include_patterns('*.dwg', '*.dxf'))

Updated: 18:21. The following code works as expected, except that I'd like to ignore folders that don't contain any include_patterns('.dwg', '.dxf')

解决方案

shutil already contains a function ignore_pattern, so you don't have to provide your own. Straight from the documentation:

from shutil import copytree, ignore_patterns

copytree(source, destination, ignore=ignore_patterns('*.pyc', 'tmp*'))

This will copy everything except .pyc files and files or

directories whose name starts with tmp.

It's a bit tricky (and not strictly necessairy) to explain what's going on: ignore_patterns returns a function _ignore_patterns as its return value, this function gets stuffed into copytree as a parameter, and copytree calls this function as needed, so you don't have to know or care how to call this function _ignore_patterns. It just means that you can exclude certain unneeded cruft files (like *.pyc) from being copied. The fact that the name of the function _ignore_patterns starts with an underscore is a hint that this function is an implementation detail you may ignore.

copytree expects that the folder destination doesn't exist yet. It is not a problem that this folder and its subfolders come into existence once copytree starts to work, copytree knows how to handle that.

Now include_patterns is written to do the opposite: ignore everything that's not explicitly included. But it works the same way: you just call it, it returns a function under the hood, and coptytree knows what to do with that function:

copytree(source, destination, ignore=include_patterns('*.dwg', '*.dxf'))

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