ntpath.py 文件源码

def normcase(s):
    """Normalize case of pathname.

    Makes all characters lowercase and all slashes into backslashes."""
    s = os.fspath(s)
    try:
        if isinstance(s, bytes):
            return s.replace(b'/', b'\\').lower()
        else:
            return s.replace('/', '\\').lower()
    except (TypeError, AttributeError):
        if not isinstance(s, (bytes, str)):
            raise TypeError("normcase() argument must be str or bytes, "
                            "not %r" % s.__class__.__name__) from None
        raise


# Return whether a path is absolute.
# Trivial in Posix, harder on Windows.
# For Windows it is absolute if it starts with a slash or backslash (current
# volume), or if a pathname after the volume-letter-and-colon or UNC-resource
# starts with a slash or backslash.