How to parse this nested dictionary datastructure in Python 3?

Question

I have a dictionary (named dict1) that has the following structure:

dict1 = {
    'Classroom': [{
        'Subject': "Calculus",
        'Students': [
            {'Name': "Joe", 'Age': 12, 'Weight': 126, 'Gender': "Male"},
            {'Name': "Doug", 'Age': 13, 'Weight': 95, 'Gender': "Male"},
            {'Name': ..., 'Age': ..., 'Weight': ..., 'Gender': ...}
        ]
    }]
}

The list (which contains name, age, weight, and gender) within this dictionary is very long, and I wanted to parse the Name, Age, and Gender out, and append them onto another list like this:

mylist = [("Joe", 12, "Male"), ("Doug", 13, "Male"), ... ]

I tried seraching online and tinkered around with code such as this:

mylist = []
dict2 = dict1['Classroom'][0]['Students'][0]['Name']
mylist.append(dict2)

But what happens is that it only appends the first name (Joe). Furthermore, I'm not sure how to parse three items (name, age, and gender) at the same time. Does anyone have a way to do this without having to use libraries?

@Ṁữŀlɪgắnậcễơưṩᛗ Apologies, I updated it. The original dict is the first dictionary that I wrote on my post. — F16Falcon
– F16Falcon, Commented Jul 27, 2019 at 19:05
The dictionary 'dict' consists of just one parent key and the value is a list. — Ṃųỻịgǻňạcểơửṩ
– Ṃųỻịgǻňạcểơửṩ, Commented Jul 27, 2019 at 19:08
@Ṁữŀlɪgắnậcễơưṩᛗ Correct, but there are dictionaries within that list, which is why I tried doing the "dict['classoom'][0]" thing to specify what items in the lists I want. But it only prints one name for some reason... — F16Falcon
– F16Falcon, Commented Jul 27, 2019 at 19:11

F16Falcon · Accepted Answer · 2019-07-27 19:20:59Z

2

Your dict1 contains one key, 'Classroom' whose value is a list with one entry. That entry, is also a dict which contains two keys. You want the 'Students' key as that contains the list of all the students. It is a list. Iterate through that list and group the fields into a tuple.

It is technically a list ['Students'] nested within a dictionary ['Classroom'][0] within a list ['Classroom'] within a dictionary dict.

The code will be

mylist = []
studentlist = dict1['Classroom'][0]['Students']
for s in studentlist:
    m = (s['Name'], s['Age'], s['Gender'])
    mylist.append(m)

For the test case

classroom = {'Classroom': 
    [{'Subject': "Calculus", 'Students': 
        [
        {'Name': "Joe", 'Age': 12, 'Weight': 126, 'Gender': "Male"}, 
        {'Name': "Doug", 'Age': 13, 'Weight': 95, 'Gender': "Male"},
        {'Name': "Omg", 'Age': 50, 'Weight': 99, 'Gender': "Female"}
        ]
    }]
}

you will end up with

[('Joe', 12, 'Male'), ('Doug', 13, 'Male'), ('Omg', 50, 'Female')]

edited Jul 27, 2019 at 19:20

F16Falcon

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answered Jul 27, 2019 at 19:11

Ṃųỻịgǻňạcểơửṩ

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1 Comment

F16Falcon Over a year ago

This works, thanks! I was also just now thinking of using "for s in studentlist", so good to know that I'm learning! :)

Krishna Kumar · Accepted Answer · 2019-07-31 15:33:49Z

1

student_list = []
classroom_list =  dict1['Classroom']
# this is the first iteration list
for classroom in classroom_list:
    student_list = classroom['Students']
    # this is the second iteration list
    for student in student_list:
        student_list.append(student['Name'], student['Age'], student['Gender'])

#student_list = [("Joe", 12, "Male"), ("Doug", 13, "Male"), ... ]

answered Jul 31, 2019 at 15:33

Krishna Kumar

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