Summing a column in a .csv file using python

Question

I'm trying to sum a column in a csv file using python. Here's a sample of the csv data;

Date,Profit/Losses
Jan-2010,867884
Feb-2010,984655
Mar-2010,322013
Apr-2010,-69417
May-2010,310503
Jun-2010,522857
Jul-2010,1033096
Aug-2010,604885
Sep-2010,-216386

I want to sum the Profit/Losses column. I am using the following code but it's returning a 0. Where could I be going wrong?

import os
import csv

# Path to collect data from the csv file in the Resources folder
pybank_csv = os.path.join("resources", "budget_data.csv")

with open(pybank_csv, 'r') as csvfile:       
   csvreader = csv.reader(csvfile, delimiter=',')
   next(csvfile, None)    
   t = sum(float(row[1]) for row in csvreader)

   #print the results
   print(f"Total: {t}")

The code seems to be perfectly fine. Please check that you are opening the right file and that Profit/Losses column doesn't sum up to 0 in reality (for example by leaving just a few first rows in it) — fdermishin
– fdermishin, Commented Dec 4, 2020 at 22:13
@fdermishin thanks for that. I am opening the correct file and the total of the column in the CSV file is not 0. — Thomas M
– Thomas M, Commented Dec 4, 2020 at 22:17
I ran the code on the sample you provided and got output Total: 4360090.0 — fdermishin
– fdermishin, Commented Dec 4, 2020 at 22:21
I've added this code ' row_count = sum(1 for row in csvreader)' and it returns '9' so I know it's reading the correct file but I'm still getting a 0 — Thomas M
– Thomas M, Commented Dec 4, 2020 at 22:32
ooh yes that could be where I am going wrong. I was reading the rows counts and then trying to sum using the 'code' csvreader. — Thomas M
– Thomas M, Commented Dec 4, 2020 at 22:59

Harsh · Accepted Answer · 2020-12-05 00:44:48Z

1

Easiest way is to use pandas library.

Use pip install pandas to install pandas on your machine

and then

import pandas as pd
df = pd.read_csv('your_filename.csv')
sumcol = df['Profit/Losses'].sum()
print(sumcol)

The sum is in sumcol object now. For future reference, If your task is to work with the data provided in csv file, pandas is a blessing. This library provides you with thousands of different types of operations you could perform on your data. Refer Pandas Website for more info.

If you want to make use of csv package only then you can read the csv as a dict and then sum the Profit/Loss entry of dict for each row

total = 0
with open('your_filename.csv', newline='') as csvfile:
    data = csv.DictReader(csvfile)
    for row in data:
        total = total + int(row['Profit/Losses'])
print(total)

Or If you want to use reader instead of dict reader, you need to ignore first row. Something like this

total = 0
with open('your_filename.csv', newline='') as csvfile:
    data = csv.reader(csvfile)
    for row in data:
        if not str(row[1]).startswith('P'):
            total = total + int(row[1])
 print(total)

edited Dec 5, 2020 at 0:44

answered Dec 4, 2020 at 22:09

Harsh

3722 silver badges15 bronze badges

Sign up to request clarification or add additional context in comments.

3 Comments

Thomas M Over a year ago

Thanks for that. This is for a class assignment and the instructor doesn't want us to use pandas just yet. That's for next week. Just wondering why the code is returning a 0

Harsh Over a year ago

I tested my code and sumcol prints 4360090 as it should. Also I will edit my answer to accommodate for 'csv library only' code

Thomas M Over a year ago

Thanks for the help. It now works. I'm new to python and also stackoverflow so I really appreciate your help.

Collectives™ on Stack Overflow

Summing a column in a .csv file using python

1 Answer 1

3 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

3 Comments

Your Answer

Sign up or log in

Post as a guest

Related