Modern Python Cookbook

How to do it...

1. Define the class with a descriptive name:


        class LazyCounterStatistics: 

2. Write the initialization method to include the object to which this object will be connected:

        
def __init__(self, raw_counter:Counter): 
            self.raw_counter = raw_counter
 

We've defined a method function that takes a Counter object as an argument value. This counter object is saved as part of the Counter_Statistics instance.

3. Define some useful helper methods. Each of these is decorated with @property to make it behave like a simple attribute:


        @property 
        def sum(self): 
            return sum(f*v for v, f in self.raw_counter.items()) 
        @property 
        def count(self): 
            return sum(f for v, f in self.raw_counter.items())

4. Define the required methods for the various values. ...