Function expanduser

Lib/ntpath.py:343–387

Expand ~ and ~user constructs. If user or $HOME is unknown, do nothing.

(path)

# variable expansion.)

def expanduser(path):
    """Expand ~ and ~user constructs.

    If user or $HOME is unknown, do nothing."""
    path = os.fspath(path)
    if isinstance(path, bytes):
        seps = b'\\/'
        tilde = b'~'
    else:
        seps = '\\/'
        tilde = '~'
    if not path.startswith(tilde):
        return path
    i, n = 1, len(path)
    while i < n and path[i] not in seps:
        i += 1

    if 'USERPROFILE' in os.environ:
        userhome = os.environ['USERPROFILE']
    elif 'HOMEPATH' not in os.environ:
        return path
    else:
        drive = os.environ.get('HOMEDRIVE', '')
        userhome = join(drive, os.environ['HOMEPATH'])

    if i != 1: #~user
        target_user = path[1:i]
        if isinstance(target_user, bytes):
            target_user = os.fsdecode(target_user)
        current_user = os.environ.get('USERNAME')

        if target_user != current_user:
            # Try to guess user home directory.  By default all user
            # profile directories are located in the same place and are
            # named by corresponding usernames.  If userhome isn't a
            # normal profile directory, this guess is likely wrong,
            # so we bail out.
            if current_user != basename(userhome):
                return path
            userhome = join(dirname(userhome), target_user)

    if isinstance(path, bytes):
        userhome = os.fsencode(userhome)

    return userhome + path[i:]


# Expand paths containing shell variable substitutions.