CODEWITHSUNDEEP
pythonlistcsvconditional-statements
HilaryKoerner
HilaryKoerner

Reputation: 61

How do I loop through a csv file and create a list based on the values in the list?

I have a csv file with three columns (ID, county, and candidate). There are four candidates and I need to create four lists (one for each candidate). Every time a candidate's name is in the list/column, I want to add that name to a new list and then get the length of that last to see how many votes they received. When I run the script, it sucesfully prints the total number of votes cast, but the length of each candidate list is printing "0" so I dont think they are successfully getting added to the list.

I am fairly new to python. I believe my error is with how I am looping and my if statements.

Thank you.

with open(poll_path, 'r') as csvfile:
    csvreader = csv.reader(csvfile, delimiter=',')

#skip the header
    next(csvreader,None)

python/
    votes = 0
    votes = []
    candidate_list = 0
    candidate_list = []
    khan = 'Khan'
    khan = []
    kahn = 0
    correy = "Correy"
    correy = []
    correy = 0
    li = "Li"
    li = []
    li = 0
    otooley = "O'Tooley"
    otooley = []
    otooley = 0
    for row in csvreader:
        votes_cast=str(row[0])
        votes.append(votes_cast)
        candidates=str(row[2])
        candidate_list.append(candidates)
        if row[2] == str(khan):
            khan.append(candidate_list)
            
        if row[2] == str(correy):
            correy.append(candidate_list)
            
        if row[2] == str(li):
            li.append(candidate_list)

        if row[2] == str(otooley):
            otooley.append(candidate_list)
            
    total_votes = len(votes)
    print("Election Results")
    print("----------------------------")
    print("Total Votes: " + str(total_votes))
    print("----------------------------")
    kahn_votes = len(khan)
    print(kahn_votes)
    correy_votes = len(correy)
    print(correy_votes)
    li_votes = len(li)
    print(li_votes)
    otooley_votes = len(otooley)
    print(otooley_votes)

Upvotes: 0

Views: 1014

Answers (1)

tdelaney
tdelaney

Reputation: 77407

You have many problems with your code. When you assign a variable multiple times as in

khan = 'Khan'
khan = []
kahn = 0

You keep losing the earlier values. kahn is 0 and the string and list are gone. Those first two lines were pointless.

votes_cast=str(row[0])

The csv module only creates strings, no need to str a string.

if row[2] == str(khan):

You know how khan is 0? Yeah, this just compares row 2 to the string "0", so i fails. Since khan was expected to be string in the first place, you shouldn't have cast it either.

There is a much better way to do this using a dictionary to track candidate counts. General notes on the code

  • use a dictionary to track candidate counts
  • don't explicitly use defaults. open("foo", "r") should be open("foo")
  • don't hard code candidates, just use what's in the file
  • unpack the csv rows into variables for readability

The code

import csv

candidate_count = {}

with open(poll_path, newline=None) as csvfile:
    csvreader = csv.reader(csvfile)
    for ID, county, candidate in csvreader:
        if candidate not in candidate_count:
            candidate_count[candidate] = 0
        candidate_count[candidate] += 1

# we can sort by total counts to print
for candidate, votes in sorted(candidate_count.items(), key=lambda kv: kv[1]):
    print(candidate, votes)

Upvotes: 1

Related Questions