How would I adjust my Python code for a nested .JSON tree (Python dictionary) to include multiple keys?

Question

In my current code, it seems to only take into account one value for my Subject key when there should be more (you can only see Economics in my JSON tree and not Maths). I've tried for hours and I can't get it to work.

Here is my sample dataset - I have many more subjects in my full data set:

ID,Name,Date,Subject,Start,Finish
0,Ladybridge High School,01/11/2019,Maths,05:28,06:45
0,Ladybridge High School,02/11/2019,Maths,05:30,06:45
0,Ladybridge High School,01/11/2019,Economics,11:58,12:40
0,Ladybridge High School,02/11/2019,Economics,11:58,12:40
1,Loreto Sixth Form,01/11/2019,Maths,05:28,06:45
1,Loreto Sixth Form,02/11/2019,Maths,05:30,06:45
1,Loreto Sixth Form,01/11/2019,Economics,11:58,12:40
1,Loreto Sixth Form,02/11/2019,Economics,11:58,12:40

Here is my Python code:

timetable = {"Timetable": []}
with open("C:/Users/kspv914/Downloads/Personal/Project Dawn/Timetable Sample.csv") as f:
    csv_data = [{k: v for k, v in row.items()} for row in csv.DictReader(f, skipinitialspace=True)]

    name_array = []
    for name in [row["Name"] for row in csv_data]:
        name_array.append(name)
    name_set = set(name_array)

    for name in name_set:
        timetable["Timetable"].append({"Name": name, "Date": {}})

    for row in csv_data:
        for entry in timetable["Timetable"]:
            if entry["Name"] == row["Name"]:
                entry["Date"][row["Date"]] = {}
                entry["Date"][row["Date"]][row["Subject"]] = {
                    "Start": row["Start"],
                    "Finish": row["Finish"]
                }

Here is my JSON tree:

In my JSON tree, you can only see the subject Economics...where has Maths gone? — Raf A
– Raf A, Commented Nov 21, 2019 at 12:47

Jay Patel · Accepted Answer · 2019-11-21 12:56:57Z

2

You're making date dict empty and then adding a subject.

Do something like this:

timetable = {"Timetable": []}
with open("a.csv") as f:
    csv_data = [{k: v for k, v in row.items()} for row in csv.DictReader(f, skipinitialspace=True)]

    name_array = []
    for name in [row["Name"] for row in csv_data]:
        name_array.append(name)
    name_set = set(name_array)

    for name in name_set:
        timetable["Timetable"].append({"Name": name, "Date": {}})

    for row in csv_data:
        for entry in timetable["Timetable"]:
            if entry["Name"] == row["Name"]:
                if row["Date"] not in entry["Date"]:
                    entry["Date"][row["Date"]] = {}
                entry["Date"][row["Date"]][row["Subject"]] = {
                    "Start": row["Start"],
                    "Finish": row["Finish"]
                }

I've just added if condition before assigning {} to entry["Date"][row["Date"]]

It will give output like as shown in the below image:

answered Nov 21, 2019 at 12:56

Jay Patel

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1 Comment

Raf A Over a year ago

Much appreciated. Any idea how I would add additional data (no nested data) that is on the same level as "Name" (no nested data) and "Date" (contains nested data)?

Tim · Accepted Answer · 2019-11-21 13:03:07Z

0

You are overwriting your dict entries with entry["Date"][row["Date"]][row["Subject"]] =. The first time "math" is met, the entry is created. The second time it is overwritten.

Your expected result should be a list, not a dict. Every entry should be appended to the list with timetable_list.append().

Here is a simple code that converts the whole csv file into Json without loosing data:

import csv
import json

data = []

with open("ex1.csv") as f:
    reader = csv.DictReader(f)
    for row in reader:
        data.append(row)

print(json.dumps({"Timetable": data}, indent=4))

answered Nov 21, 2019 at 13:03

Tim

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