Lecture_10

Let's begin the class notes immediately:

@Objects:
Objects represent information. They consist of data and behavior, bundled together to create abstractions.
Objects can reprent things, but also properties, interactions, & processes.

A type of object is called a class. Classes are first-class values in Python.

@Object-oriented programming:
a metaphor for organizing large programs.

In Python, every value is an object.
All objects have attributes.

A lot of data manipulation happen through object methods.

Functions do one thing, objects do many related things.

Example(1):
from datetime import date
firstmeet = date(2014, 6, 16)
current = date(2014, 7, 21)
str(firstmeet - current)
firstmeet.day
firstmeet.year
firstmeet.strftime("%A %B %d")

@Pairs

pair = (1, 2) # a tuple, yes.
x,y = pair
>>> pair[0]
1
>>> pair[1]
2
from operator import getitem
>>> getitem(pair, 0)
1
>>> getitem(pair, 1)
2

Example(2):
from fractions import gcd
def rational(n, d)
    """Reduce the n/d to its lowest form."""
    g = gcd(n, d)
    return (n // g, d // g)


@ Data Abstraction:
compound objects combine objects together.

An abstract data type lets us manipulate compound objects as units.