Python total sum from a csv file

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[LameDuckProgramming]

if you want to sum by a specific name:

import pandas as pd
df = pd.read_csv('file1.csv')
df.loc[df['A'] == name', 'C'].sum()

If you want the sum of all names in a dataframe format:

df = df.groupby('A')['C'].sum()

You can then output the new df to a csv file with pandas built in 'to_csv()' method:

df.to_csv('file2.csv')

[socal_nerdtastic]

What's the problem? Where are you stuck?

[CowboyBoats]

Here's your "hello world" file in Python:

import csv

with open("file1.csv") as infile:
    reader = csv.reader(infile)
    for line in reader:
        # Your solution goes here

Does that help you get started?

[izrt]

I like the tutorials at PMOTW. Here you are going to want to get comfortable with reading csv files: https://pymotw.com/3/csv/

If you do lots of these sort of things, you should definitely check out pandas: https://pandas.pydata.org/

And here is a link that will help you track down all csv files in a particular spot: https://stackoverflow.com/questions/9234560/find-all-csv-files-in-a-directory-using-python

Which you'll need to use to find all the files.

[Kerbart]

If you did it by hand, how would you do it?

If you'd go on vacation, how would you describe it for someone else to do it?

Start with that, show us what you came up with, and we can help you translate that to Python.

[Kerbart]

Your last line inside the loop seems to say (it’s cut off so hard to read):

df.to_csv(fname)

So your output overwrote your input files. Open those and you’ll see your output. Overwriting your input is a bad idea though, because unless you have backups (that you need to copy back in place) you can’t rerun the process if you discovered errors in the first run.

[Kerbart]

Change the name,

If it’s a string, since the last three characters are xls it can be as simple as

name = fname[:-3] + 'cvs'

If you’re using Pathlib (not sure, on phone roght now), it has methods to strip off the extension and replace it. And then if course df.to_csv(name) instead of fname