Programming Assignment 2 (Voting)

v1.dat (Large data file for Simple Voting)
v2.dat (Large data file for Ranked Voting)

Simple Voting Scheme

Write a Python program that reads a file containing votes indicated by name of candidate, one per line, and counts and declares the winner (candidate with most number of votes). If there is a tie for first place, all candidates are declared the winner. Here are the contents of a possible input file and a sample run of the program:

mirage:02-vote raj$ more vote1.dat 
Red
Blue
Green
Blue
Blue
Red
mirage:02-vote raj$ python3 Vote1.py vote1.dat 
Votes:  ['Red', 'Blue', 'Green', 'Blue', 'Blue', 'Red']
Winner:  Blue

Here is an example with a tie for first place:

mirage:02-vote raj$ more vote1.dat 
Red
Blue
Green
Blue
Blue
Red
Red
mirage:02-vote raj$ python3 Vote1.py vote1.dat 
Votes:  ['Red', 'Blue', 'Green', 'Blue', 'Blue', 'Red', 'Red']
Winner:  Blue
Winner:  Red

Build your solution by implementing the following functions:

# This function takes as input a list of ballots and 
# returns a list of candidates mentioned in the ballots
# e.g. candidates(["Red","Blue","Red","Green","Red"]) should return ["Red","Blue","Green"]
def candidates(ballots):
  pass

# This function takes as input a candidate and a list of ballots and
# returns the number of votes candidate received in ballots
# e.g. voteCount("Red",["Red","Blue","Red","Green","Red"]) should return 3
def voteCount(candidate,ballots):
  pass

# This function takes as input a list of candidates and a lits of ballots and
# returns a list of vote counts for each candidate as shown in example below:
# e.g. voteCounts(["Red","Blue","Green"],["Red","Blue","Red","Green","Red"]) 
# should return [(3,"Red"),(1,"Blue"),(1,"Green")]
def voteCounts(candidates,ballots):
  pass

# This function takes the vote counts as generated as in previous function as input and
# returns list of winners.
# e.g. winners([(3,"Red"),(1,"Blue"),(1,"Green")]) should return ["Red"]
def winners(voteCounts):
  pass

# Main function that reads input from file and uses the above functions to determine
# winners and print them
def main():
  pass

Ranked Voting Scheme

Write a Python program to implement the Ranked Voting scheme. In this modified voting scheme, each ballot lists 1st preference, 2nd preference, etc. The voting ballots are again present in a text file with each line corresponding to a single ballot. The candidates are listed in preference order and are separated by commas. Here is a sample input file:

mirage:02-vote raj$ more vote2.dat 
Red,Green
Blue
Green,Red,Blue
Blue,Green,Red
Green

The method to determine the winner proceeds by eliminating candidate(s) with lowest number of 1st choice votes (if there are ties, eliminate all). This process is repeated until a single candidate remains. That candidate is declared the winner. If by eliminating candidates in any one round no candidate remains then all the candidates remaining in that round are declared the winner.

Mac-mini:02-vote raj$ python3 Vote2.py vote2.dat 
Ballots:  [['Red', 'Green'], ['Blue'], ['Green', 'Red', 'Blue'], ['Blue', 'Green', 'Red'], ['Green']]
Winner:  Green