Python3：输入为文件/目录时，如何实现对应文件遍历（含XML场景）

When you need to process either a directory (and all its XML files recursively) or a single XML file consistently in a for loop, the key is to first check the type of input path and generate the appropriate iterable. Here's a clean, reusable solution:

Step 1: Create a Helper Function #

This function will handle both directory and file inputs, returning an iterable that works seamlessly with your for loop:

import os
import glob

def get_xml_files(input_path):
    # Check if input is a valid file
    if os.path.isfile(input_path):
        # Verify it's an XML file
        if input_path.lower().endswith('.xml'):
            yield input_path
        else:
            raise ValueError(f"Input '{input_path}' is not an XML file")
    # Check if input is a valid directory
    elif os.path.isdir(input_path):
        # Recursively find all XML files in the directory
        yield from glob.iglob(os.path.join(input_path, '**', '*.xml'), recursive=True)
    # Handle invalid paths
    else:
        raise FileNotFoundError(f"Input path '{input_path}' does not exist")

Step 2: Use the Function in Your For Loop #

Now you can use this function to process both directories and files without modifying your loop logic:

Example 1: Input is a Directory #

dirs = "foo"
for file in get_xml_files(dirs):
    print(file)

Output:

foo/b.xml
foo/c.xml
foo/a.xml

Example 2: Input is an XML File #

dirs = "foo/b.xml"
for file in get_xml_files(dirs):
    print(file)

Output:

foo/b.xml

Why This Works #

• Input Validation: The function first checks if the path is a file or directory, avoiding the broken glob pattern issue from your original code (where passing a file path to {0}/**/*.xml looks for non-existent subdirectories under the file).
• Consistent Iterable: Whether you pass a directory or file, the function returns an iterator, so your for loop stays identical in both cases.
• Cross-Platform Compatibility: Using os.path.join ensures path formatting works correctly on Windows, macOS, and Linux.
• Error Handling: The function raises clear errors for invalid paths or non-XML files, making debugging easier.

Alternative: Simplified Version (Without Error Handling) #

If you prefer a more concise version that skips non-XML files instead of raising errors:

import os
import glob

def get_xml_files(input_path):
    if os.path.isfile(input_path):
        if input_path.lower().endswith('.xml'):
            yield input_path
    elif os.path.isdir(input_path):
        yield from glob.iglob(os.path.join(input_path, '**', '*.xml'), recursive=True)

内容的提问来源于stack exchange，提问作者rodee