Python 小技巧：路径标准化函数

开发目的

在实际工作中，笔者经常遇到特殊的文件夹路径或者文件路径，由于缺乏经验需要在此浪费较多时间。进而想要写一个路径标准化函数，用 pathlib 包替换 os 包，把输入路径转成标准的可读格式，即输入可能是带有双引号的路径或者路径间隔是“\”、“\”、“/” 等转成标准格式。

原代码

    def normalize_path(path):
        path = re.sub(r'^["\']|["\']$', '', path.strip())
        path = path.replace('/', '\\')
        path = path.replace('\\\\', '\\')
        return path

优化过程

1.0

• 使用pathlib内置方法，这些方法通常是用C实现的，效率高
• 优先考虑了绝对路径和相对路径、内存和避免Path的报错

from pathlib import Path
import os

def normalize_path(path_input: str) -> Path:
    """
    Convert input path string to standardized Path object.
    Handles quotes, different separators, and resolves relative paths.
    """
    # Remove quotes and extra whitespace
    clean_path = path_input.strip().strip('"').strip("'")
    
    # Convert to Path object and resolve to absolute path
    try:
        path = Path(clean_path).resolve()
        return path
    except (OSError, ValueError):
        # Return unresolved path if resolution fails
        return Path(clean_path)

2.0

• 使用pathlib.Path自动处理不同操作系统的路径分隔符
• 优化去除字符串两端的引号和空格
• 当路径可解析时，使用resolve()方法解析相对路径和符号链接，返回最准确的解析结果
• 当路径不可解析时，提供合理的回退方案，回退到使用absolute()方法

import os
import logging
from pathlib import Path
from typing import Union

def normalize_path(input_path: Union[str, Path]) -> Path:
    """
    标准化路径函数
    
    将带有各种引号、不同分隔符的路径转换为标准的Path对象
    处理以下情况：
    - 去除双引号、单引号
    - 统一处理"\\"、"/"和"\"分隔符
    - 解析相对路径和特殊符号(如".", "..")
    
    参数:
        input_path: 输入的路径字符串或Path对象
        
    返回:
        标准化的Path对象
    """
    # 如果已经是Path对象，直接返回
    if isinstance(input_path, Path):
        return input_path.resolve()
    if not isinstance(input_path, (str, Path)):
    	raise TypeError(f"输入路径必须是字符串或Path对象，收到 {type(input_path)}")
    	
    # 移除字符串两端的引号和空格
    path_str = str(input_path).strip(' \t\n"\'')
    # 使用Path创建路径对象，pathlib会自动处理不同平台的分隔符
    path_obj = Path(path_str)
    
    # 解析路径（解决相对路径、符号链接等）
	try:
	    return path_obj.resolve()
    except (OSError, PermissionError, FileNotFoundError) as e:
    	# 记录错误日志
        logging.warning(f"文件系统错误: {e}, 使用绝对路径作为回退方案")
        return path_obj.absolute() # 返回绝对路径作为回退方案
	except Exception as e:
	    logging.warning(f"路径解析失败: {e}, 使用绝对路径作为回退方案")
	    return path_obj.absolute() # 返回绝对路径作为回退方案

import os
import logging
from pathlib import Path
from typing import Union

def normalize_path(input_path: Union[str, Path]) -> Path:
    """
    Path normalization function.
    
    Converts paths with various quotes and different separators to a standardized Path object.
    Handles the following cases:
    - Removal of double quotes, single quotes
    - Uniform handling of "\\", "/", and "\" separators
    - Resolution of relative paths and special symbols (e.g., ".", "..")
    
    Parameters:
        input_path: Input path string or Path object.
        
    Returns:
        Normalized Path object.
    """
    
    # Type validation
    if not isinstance(input_path, (str, Path)):
        raise TypeError(f"Input path must be a string or Path object, received {type(input_path)}")
    
    # Return directly if already a Path object
    if isinstance(input_path, Path):
        return input_path.resolve()

    # Remove quotes and whitespace from both ends of the string
    path_str = str(input_path).strip(' \t\n"\'')
    
    # Create a Path object - pathlib automatically handles platform-specific separators
    path_obj = Path(path_str)
    
    # Resolve path (handles relative paths, symbolic links, etc.)
    try:
        return path_obj.resolve()
    except (OSError, PermissionError, FileNotFoundError) as e:
        # Log error
        logging.warning(f"Filesystem error: {e}, proceeding with absolute path as fallback")
        return path_obj.absolute() # Return absolute path as fallback solution
    except Exception as e:
        # Log error
        logging.warning(f"Unknown error encountered during path resolution: {e}, returning absolute path")
        return path_obj.absolute() # Return absolute path as fallback solution