AttributeError: 'unicode' object has no attribute 'pop'

问题

I have this piece of python code in gae.

def post(self):
    cases=self.request.get('cases')
    while cases:
        logging.info("cases: %s " % cases)
        case=cases.pop()

Which produces this log.

INFO     2012-09-19 20:23:50,690 views.py:674] cases: [u'court1150'] 
ERROR    2012-09-19 20:23:50,690 webapp2.py:1553] 'unicode' object has no attribute 'pop'
Traceback (most recent call last):
  File "/Applications/GoogleAppEngineLauncher.app/Contents/Resources/GoogleAppEngine-default.bundle/Contents/Resources/google_appengine/lib/webapp2/webapp2.py", line 1536, in __call__
    rv = self.handle_exception(request, response, e)
  File "/Applications/GoogleAppEngineLauncher.app/Contents/Resources/GoogleAppEngine-default.bundle/Contents/Resources/google_appengine/lib/webapp2/webapp2.py", line 1530, in __call__
    rv = self.router.dispatch(request, response)
  File "/Applications/GoogleAppEngineLauncher.app/Contents/Resources/GoogleAppEngine-default.bundle/Contents/Resources/google_appengine/lib/webapp2/webapp2.py", line 1278, in default_dispatcher
    return route.handler_adapter(request, response)
  File "/Applications/GoogleAppEngineLauncher.app/Contents/Resources/GoogleAppEngine-default.bundle/Contents/Resources/google_appengine/lib/webapp2/webapp2.py", line 1102, in __call__
    return handler.dispatch()
  File "/Applications/GoogleAppEngineLauncher.app/Contents/Resources/GoogleAppEngine-default.bundle/Contents/Resources/google_appengine/lib/webapp2/webapp2.py", line 572, in dispatch
    return self.handle_exception(e, self.app.debug)
  File "/Applications/GoogleAppEngineLauncher.app/Contents/Resources/GoogleAppEngine-default.bundle/Contents/Resources/google_appengine/lib/webapp2/webapp2.py", line 570, in dispatch
    return method(*args, **kwargs)
  File "/Users/brian/googleapps/scheduler/views.py", line 675, in post
    case=cases.pop()
AttributeError: 'unicode' object has no attribute 'pop'

On the other hand with this almost identical code in the interactive console.

cases = [u'court1150'] 
while cases:
    case=cases.pop()
    print case
print cases

I get no error and the following print out.

court1150
[]

Why am I getting a unicode error in the gae launcher and how can I fix it?

回答1:

self.request.get('cases') does not return a list of values, it returns just one value. Try using get_all('cases') instead:

def post(self):
    cases=self.request.get_all('cases')
    while cases:
        logging.info("cases: %s " % cases)
        case=cases.pop()

There is no need to use a while loop, a for loop works much better:

def post(self):
    cases=self.request.get_all('cases')
    logging.info("cases: %s " % cases)
    for case in cases:
        # do something with case.

来源：https://stackoverflow.com/questions/12502612/attributeerror-unicode-object-has-no-attribute-pop

标签

python

google-app-engine

unicode

webapp2