lec11.5.py

# lec11.5.py
#
# Lecture 11 - Classes
# Video 5
# Example Class: A Set of Integers
#
# edX MITx 6.00.1x
# Introduction to Computer Science and Programming Using Python

class intSet(object):
    """An intSet is a set of integers
    The value is represented by a list of ints, self.vals.
    Each int in the set occurs in self.vals exactly once."""

    def __init__(self):
        """Create an empty set of integers"""
        self.vals = []

    def insert(self, e):
        """Assumes e is an integer and inserts e into self"""
        if not e in self.vals:
            self.vals.append(e)

    def member(self, e):
        """Assumes e is an integer
        Returns True if e is in self, and False otherwise"""
        return e in self.vals

    def remove(self, e):
        """Assumes e is an integer and removes e from self
        Raises ValueError if e is not in self"""
        try:
            self.vals.remove(e)
        except:
            raise ValueError(str(e) + ' not found')

    def __str__(self):
        """Returns a string representation of self"""
        self.vals.sort()
        return '{' + ','.join([str(e) for e in self.vals]) + '}'



# s = intSet()
# print s
# s.insert(3)
# s.insert(4)
# s.insert(3)
# print s
# s.member(3)
# s.member(5)
# s.insert(6)
# print s
# s.remove(3)
# print s
# s.remove(3)