Python - Nested Dictionaries

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A Python dictionary is said to have a nested structure if value of one or more keys is another dictionary. A nested dictionary is usually employed to store a complex data structure.

The following code snippet represents a nested dictionary:

marklist = {
   "Mahesh" : {"Phy" : 60, "maths" : 70},
   "Madhavi" : {"phy" : 75, "maths" : 68},
   "Mitchell" : {"phy" : 67, "maths" : 71}
}

Example 1

You can also constitute a for loop to traverse nested dictionary, as in the previous section.

marklist = {
   "Mahesh" : {"Phy" : 60, "maths" : 70},
   "Madhavi" : {"phy" : 75, "maths" : 68},
   "Mitchell" : {"phy" : 67, "maths" : 71}
}
for k,v in marklist.items():
   print (k, ":", v)

It will produce the following output −

Mahesh : {'Phy': 60, 'maths': 70}
Madhavi : {'phy': 75, 'maths': 68}
Mitchell : {'phy': 67, 'maths': 71}

Example 2

It is possible to access value from an inner dictionary with [] notation or get() method.

print (marklist.get("Madhavi")['maths'])
obj=marklist['Mahesh']
print (obj.get('Phy'))
print (marklist['Mitchell'].get('maths'))

It will produce the following output −

68
60
71