LAB6 - World Cup

MOC CS50

Created: 2022-07-14
Tags: #fleeting

Understand the general information
Program that runs simulations of the FIfa World Cup

Soccers world cup has 16 teams
Each round,
each team plays another team
losing teams are eliminated
Until two remains and whoever the winner of that match is the winner of the overall tourna

FIFA Ratings

  • soccer teams are given this
  • Higher FIFA ratings indicate better previous game results

Given two teams with their own fifa ratings, we can guess whoever win the round

Using this information,

  • we can simulate the entire tournament by repeatedly simulating rounds until we’re left with just one team.
  • And if we want to estimate how likely it is that any given team wins the tournament, we might simulate the tournament many times (e.g. 1000 simulations)
  • and count how many times each team wins a simulated tournament.

Understand the Code
We got two .csv files and the .py code

team,rating     
Uruguay,976
Portugal,1306

I think I can say that the two .csv files

  • doesn't have similar teams comparing the two .csv files

The order in which the teams are listed
-> determines which teams will play each other in each round
Example:
in the first round,
Uruguay will play Portugal and
France will play Argentina;
#myquestion So does that mean that 1st round consists of all teams, like Brazil vs Mexico, Beligun vs Japan till the last team which is Colombia vs England?????? Yeah I think it is because the simulate_round returns the list of all of the teams that won the round.
in the next round,
the winner of the Uruguay-Portugal match will play the winner of the France-Argentina match).
So be sure not to edit the order in which teams appear in this file!

Functions Explained (Already implented)
The simulate_game function accepts two teams as inputs
(recall that each team is a dictionary containing the team name and the team’s rating), and simulates a game between them.
If -> first team wins, the function returns True
ELSE -> the function returns False. Assumes that the 2nd team wins

The simulate_round function accepts a list of teams (in a variable called teams) as input, and simulates games between each pair of teams.
The function returns a list of all of the teams that won the round.

Main Function
Finally, at the end of main, we sort the teams in descending order of how many times they won simulations (according to counts) and print the estimated probability that each team wins the World Cup.

Functions or Code that we are going to implement
First, in main,

  • read the team data from the CSV file into your program’s memory,
  • add each team to the list teams.
    The file to use will be provided as a cli arg. You can access the name of the file, then, with sys.argv[1].
    csv.DictReader function to read the csv file
    By default, all values read from the file will be strings. convert the team’s rating to an int
    Ultimately, append each team’s dictionary to teams. The function call teams.append(x) will append x to the list teams.
teams = []
file = sys.argv[1]
with open(file) as csv_file: 
    dictionary = csv.DictReader(csv_file)
    for team in dictionary:
        teams.append(team)

Do we still need to remember the .csv file outside of this particular code?
Ans: I don't think so, okay so I guess we can safely use with

  • Experiement with dictionary
  • How do we make the particular value transform into an int?
    - [x] I could read the article about dictionaries in python. That will also lead us to learn more about dictionaries in python.
    Basically like this
{'team': 'Urugay', 'rating': '976'}
And I want it to be like this below
{'team': 'Urugay', 'rating': 976}

append each team’s dictionary to teams. The function call teams.append(x) will append x to the list teams.

  • What should I expect the teams list value is gonna be?
    Ans: Okay, so I'm expecting that it's just gonna be the name of the teams, not their ratings???
    Different Ans: Hmm no, I think the teams variable is gonna be a list of dictionary representing the team name and their rating. And the rating is expected to be int
    ~~- [ ] So where will I put the ratings value? Will I need to create a new list?

Code Plan to add values to teams

for team in dictionary:
    # Replace the value of key rating to an int
    teams.append(team)
  • Let's first learn how to GET the value of a particular key
dictionary.get('name_of_key')
  • Then let's learn how to REPLACE a value of a particular key
dictionary['name_of_key'] = 'new value to update the old value of key'

So in conclusion

for team in dictionary:
    team['rating'] = int(team.get('rating'))  # Replace string to int
    teams.append(team)

Overall

teams = []
file = sys.argv[1]
with open(file) as csv_file: 
    dictionary = csv.DictReader(csv_file)
    for team in dictionary:
        team['rating'] = int(team.get('rating'))  # Replace string to int
        teams.append(team)

So I'm confident that the first ting is now solve

Simulate Tournament
input a list of teams and
should repeatedly simulate rounds until you’re left with one team.
return the name of the one team that's left
You can call the simulate_round function, which simulates a single round, accepting a list of teams as input and returning a list of all of the winners.
- You should not assume the number of teams in the tournament, but you may assume it will be a power of 2.

teams = [
{'team': 'Uruguay', 'rating': 976}, 
{'team': 'Portugal', 'rating': 1306}
]

Algo:
Call simulate round
then it will return all of the winners
Check if the length of the new winners are one team
If not, then return step 1

Code:

winners = teams
while len(winners) == 1:
    winners = simulate_round(winners)
return winners.get('team')  # return the name of team

Okay, so this is my final code, I'm not quite sure if its correct or not

Back to main function
For example,
IF -> Uruguay won 2 tournaments and Portugal won 3 tournaments,
THEN -> your counts dictionary should be {"Uruguay": 2, "Portugal": 3}.

Use your simulate_tournament to simulate each tournament and determine the winner.

  • Recall that if counts is a dictionary, then syntax like counts[team_name] = x will associate the key stored in team_name with the value stored in x.
  • You can use the in keyword in Python to check if a dictionary has a particular key already. For example, if "Portugal" in counts: will check to see if "Portugal" already has an existing value in the counts dictionary.
counts = {}
    # TODO: Simulate N tournaments and keep track of win counts
    for i in range(0, N):
        team_winner = simulate_tournaments(teams)
  • Checking if a particular key is already in the dictionary
    Ans: You can use the in keyword in Python to check if a dictionary has a particular key already.

Algo:
If a team is in dictionary:
increment the value pair of that
Else (assumes team is not in dictionary):
create a key-value pair with
the default value of 1
key will be the team name

  • Learn how to add key-value pair into dictionary

Code

if winner in count:
    count[winner] += 1
else:  # Assumes team is not in count dictionary
    count[winner] = 1

Okay, so my code now works. I had to do some adjustments here in there
But I have no idea if logically, there's no error on it

Well done :D
FINAL CODE

# Simulate a sports tournament

import csv
import sys
import random

# Number of simluations to run
N = 1000


def main():

    # Ensure correct usage
    if len(sys.argv) != 2:
        sys.exit("Usage: python tournament.py FILENAME")

    teams = []
    # TODO: Read teams into memory from file
    file = sys.argv[1]
    with open(file) as csv_file:
        dictionary = csv.DictReader(csv_file)
        for team in dictionary:
            team['rating'] = int(team.get('rating'))  # Replace string to int
            teams.append(team)


    counts = {}
    # TODO: Simulate N tournaments and keep track of win counts
    for i in range(0, N):
        winner = simulate_tournament(teams)
        if winner in counts:
            counts[winner] += 1
        else:  # Assumes team is not in count dictionary
            counts[winner] = 1

    # Print each team's chances of winning, according to simulation
    for team in sorted(counts, key=lambda team: counts[team], reverse=True):
        print(f"{team}: {counts[team] * 100 / N:.1f}% chance of winning")


def simulate_game(team1, team2):
    """Simulate a game. Return True if team1 wins, False otherwise."""
    rating1 = team1["rating"]
    rating2 = team2["rating"]
    probability = 1 / (1 + 10 ** ((rating2 - rating1) / 600))
    return random.random() < probability


def simulate_round(teams):
    """Simulate a round. Return a list of winning teams."""
    winners = []

    # Simulate games for all pairs of teams
    for i in range(0, len(teams), 2):
        if simulate_game(teams[i], teams[i + 1]):
            winners.append(teams[i])
        else:
            winners.append(teams[i + 1])

    return winners


def simulate_tournament(teams):
    """Simulate a tournament. Return name of winning team."""
    # TODO
    winners = teams
    while (len(winners) != 1):
        winners = simulate_round(winners)
    return winners[0].get('team')  # return the name of team


if __name__ == "__main__":
    main()

References

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LAB6 - World Cup
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