kundeng06 's List: python

• class Delegate:  '''Handles a list of methods and functions  Usage:  d = Delegate()  d += function # Add function to end of delegate list  d(*args, **kw) # Call all functions, returns a list of results  d -= function # Removes last matching function from list  d -= object # Removes all methods of object from list  '''  def __init__(self):  self.__delegates = []   def __iadd__(self, callback):  self.__delegates.append(callback)  return self   def __isub__(self, callback):  # If callback is a class instance,  # remove all callbacks for that instance  self.__delegates = [ cb  for cb in self.__delegates  if getattr(cb, 'im_self', None) != callback]   # If callback is callable, remove the last  # matching callback  if callable(callback):  for i in range(len(self.__delegates)-1, -1, -1):  if self.__delegates[i] == callback:  del self.__delegates[i]  return self  return self   def __call__(self, *args, **kw):  return [ callback(*args, **kw)  for callback in self.__delegates]
• class Event(property):  '''Class event notifier  Usage:  class C:  TheEvent = Event()  def OnTheEvent(self):  self.TheEvent(self, context)   instance = C()  instance.TheEvent += callback  instance.OnTheEvent()  instance.TheEvent -= callback  '''  def __init__(self):  self.attrName = attrName = "__Event_" + str(id(self))  def getEvent(subject):  if not hasattr(subject, attrName):   setattr(subject, attrName, Delegate())  return getattr(subject, attrName)  super(Event, self).__init__(getEvent)   def call(self, subject, *args, **kw):  if hasattr(subject, self.attrName):  getattr(subject, self.attrName)(subject, *args, **kw)
• count([n])

   

  Return consecutive integers starting with n

   

  ifilter(predicate, iterable)

   

  Return all elements x of iterable for which predicate(x) is true.

   

  imap(function, *iterables)

   

  Like map(), but returns an iterator rather than a list.

   

  izip(*iterables)

   

  Like zip(), except it returns an iterator.

   

  repeat(obj)

   

  Returns an iterator that yields obj an unlimited number of times.

   

  times(n, [object])

   

  Returns object a total of n times.

  • find it in python doc
• save = result.append while somecondition:  save(calculateValue())

2 more annotations...

• package_dir

  • good!

• Thus, the surround module can simply use import echo or from echo import echofilter.

• When a generator function is called, the actual arguments are bound to  function-local formal argument names in the usual way, but no code in  the body of the function is executed.

  • important!

• All this happens at the end of the class statement, after the body of the class (where methods and class variables are defined) has already been executed.
• When a class statement is executed, the interpreter first determines the appropriate metaclass M, and then calls M(name, bases, dict).
• How is M determined?
• cls = M.__new__(M, name, bases, dict)
• M.__init__(cls, name, bases, dict)

3 more annotations...

• If __setattr__() wants to assign to an instance attribute, it  should not simply execute "self.name = value" -- this would cause a recursive call to itself. Instead, it should insert the value in the dictionary of instance attributes, e.g., "self.__dict__[name] = value". For new-style classes, rather than accessing the instance dictionary, it should call the base class method with the same name, for example, "object.__setattr__(self, name, value)".

• which is the first place
• the instance's class has an attribute by that name, the search continues with the class attributes
• If no class attribute is found, and the object's class has a __getattr__() method, that is called to satisfy the lookup.
• class has a __setattr__() or __delattr__() method,

  • or its parents of course
• update the instance's dictionary, never a class's dictionary.

3 more annotations...

• contains only
• Observe that only __dict__ is searched,
• it exists and is a data-descriptor,
• then for the attribute in the object __dict__,
• Python first checks for a data descriptor in the type (and its bases)
• then for a non-data descriptor in the type (and its bases).
• t it doesn't work
• This goes straight to the type (calls C.__len__()), not to the instance.
• instances of this type

7 more annotations...

• The implementation adds two special read-only attributes to class instance methods: m.im_self is the object on which the method operates, and m.im_func is the function implementing the method. Calling m(arg-1, arg-2, ..., arg-n) is completely equivalent to calling m.im_func(m.im_self, arg-1, arg-2, ..., arg-n).