Wsrtjtyk

Now this program reads data from a csv, sums the values per day, and calculates the cumulative values. In the next part, I want it to save the data to a new csv file.

import csv

from collections import defaultdict, OrderedDict





def convert(data):

    try:

        return int(data)

    except ValueError:

        return 0





with open('Montdata1.csv', 'r') as file1:

        read_file = csv.reader(file1, delimiter=';')

        delheader = next(read_file)

        data = defaultdict(int)

        for line in read_file:

            valuedata = max(0, sum([convert(i) for i in line[1:5]]))

            data[line[0].split()[0]] += valuedata



        for key in OrderedDict(sorted(data.items())):

            print('{} {}'.format(key, data[key]))

        print("")

        previous_values = 

        for key, value in OrderedDict(sorted(data.items())).items():

            print('{} {}'.format(key, value + sum(previous_values)))

            previous_values.append(value)

It should be that in the column is the date, and in the second is the values. So it would be something like this:
Example picture

I have tried the following code, but it doesn't do anything:

with open('Datasave.csv', 'w', newline='') as csvfile:

    spamreader = csv.reader(csvfile, delimeter= ' ')

    for row in spamreader:

        print(', '.join(row))

Hope for some help

The data file as csv: https://files.fm/u/2vjppmgv

Data file in pastebin https://pastebin.com/Tw4aYdPc

If you just want to use your original code and write to a csv file, you can see how I did it below:

with open('Datasave.csv', 'w') as df:

    writer = csv.writer(df, delimiter=';', lineterminator='n')

    for item in data:

        writer.writerow([item] + [data[item]])

With pandas:

#!/bin/python



import pandas as pd



df = pd.read_csv('data.csv', sep=';')



df['Sum'] = df[df.columns[2:]].sum(axis=1)

new_df = df.groupby('Time').sum()



new_df['Sum'].to_frame().to_csv('new_data.csv', sep=';')

Output:

Time;Sum

1.1.2016;351087.0

2.1.2016;-2453.0

3.1.2016;0.0

With standard libraries:

import csv



dates={}



with open('data.csv', 'r') as df:

    df.readline()

    f = csv.reader(df, delimiter=';')

    for line in f:

        if line[0] not in dates:

            dates[line[0]] = sum(map(int, line[2:]))

        else:

            dates[line[0]] += sum(map(int, line[2:]))



with open('new_data.csv', 'w') as df:

    writer = csv.writer(df, delimiter=';', lineterminator='n')

    for date in dates:

        writer.writerow([date] + [dates[date]])

Output:

Time;Sum

1.1.2016;351087.0

2.1.2016;-2453.0

3.1.2016;0.0