如何从Python文件中提取函数名、文档字符串及函数体？

The cleanest and most robust way to solve this without regex or manual text parsing is to use Python's built-in ast module (Abstract Syntax Trees). AST parsing properly understands Python's syntax structure, so it handles edge cases like multi-line docstrings, nested indentation, and string literals inside function bodies that regex would struggle with.

Here's a complete implementation:

import ast

def extract_function_info(file_path):
    with open(file_path, 'r', encoding='utf-8') as f:
        source_code = f.read()
    
    tree = ast.parse(source_code)
    function_info = {}
    function_count = 1
    
    for node in ast.walk(tree):
        # To target only top-level functions, replace ast.walk(tree) with tree.body
        if isinstance(node, ast.FunctionDef):
            # Extract function name
            func_name = node.name
            
            # Extract docstring (handles multi-line automatically)
            func_doc = ast.get_docstring(node) or ""
            
            # Extract function body, excluding the docstring if present
            body_nodes = node.body
            # Check if the first body node is a docstring expression
            if (body_nodes 
                and isinstance(body_nodes[0], ast.Expr) 
                and isinstance(body_nodes[0].value, (ast.Constant, ast.Str))):
                body_nodes = body_nodes[1:]
            
            # Get original source code for each body statement
            func_body = []
            for body_node in body_nodes:
                segment = ast.get_source_segment(source_code, body_node)
                if segment:
                    func_body.append(segment)
            
            # Join body lines to preserve formatting
            func_body_str = '\n'.join(func_body)
            
            # Add to result dict
            function_info[function_count] = {
                'name': func_name,
                'docstring': func_doc,
                'body': func_body_str
            }
            function_count += 1
    
    return function_info

How to use it: #

Call the function with your target .py file path:

info = extract_function_info("your_file.py")

Testing with your example: #

For the sample code you provided, this will return exactly the dictionary structure you requested. Docstrings are extracted correctly (including multi-line ones), and the function body preserves indentation and newline characters as they appear in the original file.

Key notes: #

• Nested Functions: ast.walk will pick up functions inside other functions or classes. If you only want top-level functions, replace ast.walk(tree) with tree.body in the loop.
• No Docstrings: Functions without docstrings will have an empty string for the docstring key.
• Python Versions: ast.Constant works for Python 3.8+. For older versions, use ast.Str instead.
• Encoding: The code uses utf-8 encoding—adjust if your file uses a different encoding.

This approach is far more reliable than regex because it doesn't rely on pattern matching; it directly parses the code's structure to extract the exact information you need.

内容的提问来源于stack exchange，提问作者R32415