pathlib relative_to方法详解 - Python相对路径计算教程

Path.relative_to(other)

from pathlib import Path

# 计算相对路径
file_path = Path('/home/user/docs/report.pdf')
base = Path('/home/user')
relative = file_path.relative_to(base)
print(f"相对路径: {relative}")

# 多层嵌套
deep = Path('/home/user/projects/web/src/index.html')
relative2 = deep.relative_to(Path('/home/user/projects'))
print(f"相对路径: {relative2}")

# 输出：
# 相对路径: docs\report.pdf
# 相对路径: web\src\index.html

from pathlib import Path

# 模拟项目结构
project_root = Path.cwd()
src_file = project_root / 'src' / 'main.py'
test_file = project_root / 'tests' / 'test_main.py'
config_file = project_root / 'config' / 'settings.json'

# 计算相对于项目根目录的路径
for f in [src_file, test_file, config_file]:
    try:
        rel = f.relative_to(project_root)
        print(f"{rel}")
    except ValueError:
        print(f"{f} 不在项目根目录下")

# 输出：
# src\main.py
# tests\test_main.py
# config\settings.json

from pathlib import Path

# 路径不在基准路径下时会报错
try:
    result = Path('/usr/bin/python').relative_to(Path('/home/user'))
except ValueError as e:
    print(f"错误: {e}")

# 安全的 relative_to 封装
def safe_relative_to(path, base):
    """安全计算相对路径，无法计算时返回绝对路径"""
    try:
        return path.relative_to(base)
    except ValueError:
        return path.resolve()

p1 = Path.cwd() / 'data' / 'file.txt'
p2 = Path('/usr/bin/python')

print(f"项目内: {safe_relative_to(p1, Path.cwd())}")
print(f"项目外: {safe_relative_to(p2, Path.cwd())}")

# 输出：
# 错误: '/usr/bin/python' is not in the subpath of '/home/user'
# 项目内: data\file.txt
# 项目外: /usr/bin/python