Week 3 - Object Oriented Programming

After 2 weeks of the amazing winter break, I started my second course for the computer language Python. Started from Week 1, the professor and us discussed about the topic of Object Oriented Programming. Python is an object-oriented computer language, which makes creating and using classes much more easy. Class is a cool and efficient prototype to organize a group of functions and methods. I can utilize the class’s build-in methods and also write new functions within the class. Also, a class can build upon/from another class, called the superclass along with its subclasses. The characteristics of the superclass would also transfer to its subclasses which are derived from it. I like to use class in my codes, yet to keep track of the variables and methods within it might be a bit of more work. In addition, the required variable ‘self’ is a cool way to organize my data.

Something new that I have not encountered before, ADT – abstract data types. In the lecture, we learnt one common ADT, the stack. A stack is a way of using collections; in 108 we have learnt types of collections include dictionaries and lists. The basic methods(behaviours) for a stack consists of these functions:

           __init__:
           Initialize a new stack

           push:
           Add a new item to the stack

           pop:
           Remove and return the last item that was added to the stack.
           
           isEmpty:
           Check whether the stack is empty

A stack is a "last in, first out" structure, because it will always first remove the last item that has been added to it. We have not really had a practical lab/exercise that wanted us to use stack in, yet I think it was a very interesting way of dealing with lists and dictionaries.

          The lab the professor gave us was really interesting, because I have learnt something like a “brother” of stack – queue, where the first item added is the first item been removed (“first-in, first-out”). However, lists are not as efficient as stack by using queue. The runtime for stack is constant, yet queue is more likely to be linear; doing inserts or pops from index 0 of a list is slow  since all the items on the other index will have to shift down by one.

It was a really small thing that I will never notice and it was fun to think of the reason why queue was inefficient. Discussing question during labs was very good way of absorbing new knowledge for me; I actually think more carefully, detailed and more rounded about the topics. Therefore, I like to do labs in 148. My partner is a really smart and helpful person, I can always gain something new that I have never noticed before :D.