Pathlib 正在接受一个 os.PathLike 对象，并将其解释为 bool

Question

问题

我目前正在做的项目有一个莫名其妙的错误，要么是我太笨了，要么就是太晦涩和技术性了。

我试图首先找到一个目录，返回它的路径，然后检查其中是否存在子目录。

from pathlib import Path
from os.path import isdir
from os import getenv
from subprocess import Popen


def find_dlDir():
    example_dlHomeDirs = [
        Path(getenv("HOME"), 'downloads'),
        Path(getenv("HOME"), 'Downloads'),
    ]

    if dlHome := getenv("DOWNLOADS_HOME") != None:
        return dlHome
    else:
        for path in example_dlHomeDirs:
            if isdir(path):
                return path
        return None


def dirExists(dirName: str):
    if dlHome := find_dlHome() != None:
        if isdir(Path(dlHome, dirName)):
            return True
        else:
            return False
    else:
        print("No Downloads Folder found.\nTo resolve, create a new folder in \
            your home folder with one of the following names:")
        [print(name) for name in ['downloads', 'Downloads']]
        exit(1)


def mkdir(path: Path, dirToMake: str):
    """
    Make a directory with the name <dirToMake> at <path>

    kwargs["path"]? Parent directory of <dirToMake>
    kwargs["dirToMake"]? Name of the to-be-made directory
    """
    Popen("mkdir", f"{str(path)}/{dirToMake}")


if __name__ == "__main__":
    dir = "example"

    if not dirExists(dirName=dir):
        mkdir(path=getenv("DOWNLOADS_HOME"), dirToMake=dir)

下面的代码应该——使用下面的文件系统——运行：mkdir $HOME/Downloads/example.

/Users/dickssau000 ¬
----Downloads ¬
--------github.com
--------youtube.com
--------mega.nz

相反，我得到了回溯：

Traceback (most recent call last):
  File "/Users/dickssau000/.local/src/github.com/Saul-Dickson/dl/test.py", line 48, in <module>
    if not dirExists(dirName=dir):
  File "/Users/dickssau000/.local/src/github.com/Saul-Dickson/dl/test.py", line 24, in dirExists
    if isdir(Path(dlHome, dirName)):
  File "/usr/local/Cellar/python@3.9/3.9.1/Frameworks/Python.framework/Versions/3.9/lib/python3.9/pathlib.py", line 1071, in __new__
    self = cls._from_parts(args, init=False)
  File "/usr/local/Cellar/python@3.9/3.9.1/Frameworks/Python.framework/Versions/3.9/lib/python3.9/pathlib.py", line 696, in _from_parts
    drv, root, parts = self._parse_args(args)
  File "/usr/local/Cellar/python@3.9/3.9.1/Frameworks/Python.framework/Versions/3.9/lib/python3.9/pathlib.py", line 680, in _parse_args
    a = os.fspath(a)
TypeError: expected str, bytes or os.PathLike object, not bool

我绝对确定在第 24 行，变量 dlHome 和 dirName 分别是 os.PathLike 和 str。这些变量都不应该是 bool 类型，我完全不知道如何修复它。有人知道这里发生了什么吗？

python: 3.9

Answer 1

if dlHome := find_dlHome() != None:
    ...

这相当于

if dlHome := (find_dlHome() != None):
    ...

意思是dlHome是bool的类型，不是find_dlHome()的结果！你想要这个：

if (dlHome := find_dlHome) is not None:
    ...

（您还应该使用 is/is not 而不是 ==/!= 进行 None 检查）

Pathlib 正在接受一个 os.PathLike 对象，并将其解释为 bool

Pathlib is taking an os.PathLike object, and interpereting it as bool

python-3.x

pathlib

问题