[FIXED] Plotting additive points in pyplot?

Issue

Starting with a .csv with a format roughly like date, qualitative info, value

I've tried to plot this value in pyplot but run into the issue where I have multiple values for the same date since I don't care about the qualitative info in the .csv.

Is there a way to either add the two values together during the plotting process or to merge the lists of dicts in such a way where I can go from:

[{'interval_start_timestamp': '2021-04-13', 'leavers': 3}, {'interval_start_timestamp': '2021-04-13', 'leavers': 16}, {'interval_start_timestamp': '2021-04-14', 'leavers': 6}, {'interval_start_timestamp': '2021-04-14', 'leavers': 10}]

to:

[{'interval_start_timestamp': '2021-04-13', 'leavers': 19}, {'interval_start_timestamp': '2021-04-14', 'leavers': 16}]

keeping in mind that there are instances where a date is not repeated, is there a way to write it universally so that a new .csv in the same format would behave as desired?

Solution

Your data is in a bit of an awkward format, so I think it is best to format it to something easier to use and format it back later:

# loop over all dictionaries in the input list and reformat them
merged_dict = {} # use timestamps as keys, leavers as values
for dictionary in csv_dicts:
    timestamp = dictionary["interval_start_timestamp"]
    leavers = dictionary["leavers"]
    
    # check if a key already exists
    if dictionary["interval_start_timestamp"] in merged_dict:
        merged_dict[timestamp] += leavers
    else:
        merged_dict[timestamp] = leavers

# use the data for whatever you want
plt.plot(merged_dict.keys(), merged_dict.values())

# format back to the old format using list comprehension
reformatted_dict = [{"interval_start_timestamp": timestamp, "leavers": leavers}
                    for timestamp, leavers in merged_dict.items()]

This outputs a plot and the merged data:

>>> reformatted_dict
[{'interval_start_timestamp': '2021-04-13', 'leavers': 19}, {'interval_start_timestamp': '2021-04-14', 'leavers': 16}]

Answered By - asdf101