python - 让 os.path.join 与生成器一起工作？

Question

为了让这行代码正常工作，无论我如何更改格式，我都会遇到问题:

if not os.path.exists(os.path.join(IncludeSettings.FILE_URL, [str(x) for x in [year, month, day]])):

(year, month, day) 可以是整数或字符串。

回溯:

Traceback (most recent call last):
  File "/home/tinyup/dev/lib/python2.7/site-packages/pyramid_debugtoolbar-1.0.3-py2.7.egg/pyramid_debugtoolbar/toolbar.py", line 117, in toolbar_tween
    response = _handler(request)
  File "/home/tinyup/dev/lib/python2.7/site-packages/pyramid_debugtoolbar-1.0.3-py2.7.egg/pyramid_debugtoolbar/panels/performance.py", line 55, in resource_timer_handler
    result = handler(request)
  File "/home/tinyup/dev/lib/python2.7/site-packages/pyramid-1.4a3-py2.7.egg/pyramid/tweens.py", line 20, in excview_tween
    response = handler(request)
  File "/home/tinyup/dev/lib/python2.7/site-packages/pyramid-1.4a3-py2.7.egg/pyramid/router.py", line 161, in handle_request
    response = view_callable(context, request)
  File "/home/tinyup/dev/lib/python2.7/site-packages/pyramid-1.4a3-py2.7.egg/pyramid/config/views.py", line 342, in rendered_view
    result = view(context, request)
  File "/home/tinyup/dev/lib/python2.7/site-packages/pyramid-1.4a3-py2.7.egg/pyramid/config/views.py", line 456, in _class_requestonly_view
    response = getattr(inst, attr)()
  File "/home/tinyup/dev/tinyuploads/tinyuploads/views/share.py", line 56, in view_process
    return self.handle_file_upload(self.request.params['file'], shareID)
  File "/home/tinyup/dev/tinyuploads/tinyuploads/views/share.py", line 101, in handle_file_upload
    self.save(file, newFileName, isImage, uploadTime)
  File "/home/tinyup/dev/tinyuploads/tinyuploads/views/share.py", line 166, in save
    if not os.path.exists(os.path.join(IncludeSettings.FILE_URL, [str(x) for x in [year, month, day]])):
  File "/home/tinyup/dev/lib/python2.7/posixpath.py", line 66, in join
    if b.startswith('/'):
AttributeError: 'list' object has no attribute 'startswith'

Answer 1

你在这里错过了'*':

>>> os.path.join('foo', *['a','b'])
'foo/a/b'

为了将列表项作为解压缩的变量参数列表传递给方法，您必须在此处使用星号运算符。