Python: Convert more than one list to nested dictionary

Last update on June 28 2025 12:39:37 (UTC/GMT +8 hours)

43. Convert Multiple Lists to a Nested Dictionary

Write a Python program to convert more than one list to a nested dictionary.

Visual Presentation:

Sample Solution:

Python Code:

# Define a function 'nested_dictionary' that takes three lists as input and creates a nested dictionary structure.
def nested_dictionary(l1, l2, l3):
     # Use a list comprehension to create a list of dictionaries, each containing nested dictionaries.
     # The elements of the input lists 'l1', 'l2', and 'l3' are used to create these nested dictionaries.
     result = [{x: {y: z}} for (x, y, z) in zip(l1, l2, l3)]
     return result

# Create three lists, 'student_id', 'student_name', and 'student_grade'.
student_id = ["S001", "S002", "S003", "S004"] 
student_name = ["Adina Park", "Leyton Marsh", "Duncan Boyle", "Saim Richards"] 
student_grade = [85, 98, 89, 92]

# Print a message indicating the start of the code section and the original lists.
print("Original strings:")
print(student_id)
print(student_name)
print(student_grade)

# Print a message indicating the intention to create a nested dictionary.
print("\nNested dictionary:")

# Call the 'nested_dictionary' function and create a nested dictionary from the three input lists.
# Assign the result to the variable 'ch', which is not used further.
ch = 'a'
print(nested_dictionary(student_id, student_name, student_grade)) 

Sample Output:

Original strings:
['S001', 'S002', 'S003', 'S004']
['Adina Park', 'Leyton Marsh', 'Duncan Boyle', 'Saim Richards']
[85, 98, 89, 92]

Nested dictionary:
[{'S001': {'Adina Park': 85}}, {'S002': {'Leyton Marsh': 98}}, {'S003': {'Duncan Boyle': 89}}, {'S004': {'Saim Richards': 92}}]

Flowchart:

For more Practice: Solve these Related Problems:

• Write a Python program to merge three lists into a list of nested dictionaries using zip() and list comprehension.
• Write a Python function that takes three parallel lists (IDs, names, scores) and returns a nested dictionary for each item.
• Write a Python program to convert multiple lists into a nested dictionary where each outer key maps to a dictionary of inner key-value pairs.
• Write a Python program to build a nested dictionary from several lists while ensuring proper pairing of elements.

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