如何优化回调python代码以获得更好的可读性和pythonic实践？

Question

I have a private function that needs to be invoked from the constructor. This private function's job is to do the subscription for the events that will be notified by an external program. All the subscription functions need generic parameters like freq, initialPublication, initiallySuspended, callback and asynchronous. I want all the subscription parameters to be the same. However, the callback should vary. Here is the generic params dictionary I have created.

params = {'freq': 0, 'initialPublication': True,

                      'initiallySuspended': False, 'callback': None,

                      'asynchronous':   True,

                      }

                  

I have added a comment where I feel pretty repetitive ie

params[callback] = self.callback_test_sub1
 subscribe_attrib = 'subscribe_testSub1'
 if not self._subscribe(params, subscribe_attrib):
            return False
 ......
 

What can I do to improve this or is it already in its best form?

class Test:
    
    def callback_test_sub1(self, sub1_data):
        print('got sub1 data')
        
    def callback_test_sub2(self, sub2_data):
        print('got sub2 data')
        
    def notify_test_sub3(self, sub3_data):
        print('got sub3 data')
        
    def _subscribe(self, params, subscribe_attribute):
        try:
            func = getattr(self.external_obj, subscribe_attribute)
            err_status = func(**params)
        except AttributeError:
            print('no such attribute')

        except Exception as e:
            print(e)
    
    def __init__(self):
        params = {'freq': 0, 'initialPublication': True,
        'initiallySuspended': False, 'callback': None, 'asynchronous': True}
        
        ###  while doing these 3 callbacks, I feel repetitive
        params[callback] = self.callback_test_sub1
        subscribe_attrib = 'subscribe_testSub1'
        if not self._subscribe(params, subscribe_attrib):
            return False
        params[callback] = self.callback_test_sub2
        subscribe_attrib = 'subscribe_testSub2'
        if not self._subscribe(params, subscribe_attrib):
            return False
        params[callback] = self.callback_test_sub2
        subscribe_attrib = 'subscribe_testSub3'
        if not self._subscribe(params, notify_test_sub3):
            return False
        ###  while doing these 3 callbacks, I feel repetitive end
        return True

Answer 1

If you don't want to repeat these small blocks, you could make a list through which to iterate:

callbacks = (('subscribe_testSub1', self.callback_test_sub1), 
             ('subscribe_testSub2', self.callback_test_sub2), 
             ('subscribe_testSub3', self.callback_test_sub3))
for attribute, callback in callbacks:
    params['callback'] = callback
    if not self._subscribe(params, attribute)
        return False

Given that your code example already shows several typos/errors, it might be actually useful to reduce this repetition. If the callback and attribute names have a specific pattern, you could also compute them and retrieve with getattr , but the code might get more obscure then and cannot be verified statically.