Python: Remove duplicates from a list of lists

Last update on April 19 2025 12:59:12 (UTC/GMT +8 hours)

Remove Duplicates from List of Lists

Write a Python program to remove duplicates from a list of lists.

Visual Presentation:

Sample Solution:

Python Code:

# Import the 'itertools' module for working with iterators and grouping
import itertools

# Define a list 'num' containing sublists with integers
num = [[10, 20], [40], [30, 56, 25], [10, 20], [33], [40]]

# Print a message indicating the purpose of the following output
print("Original List", num)

# Sort the list 'num', which sorts the sublists lexicographically
num.sort()

# Use 'itertools.groupby' to group similar sublists and retain the first occurrence of each group
new_num = list(num for num, _ in itertools.groupby(num))

# Print a message indicating the purpose of the following output
print("New List", new_num)

Sample Output:

Original List [[10, 20], [40], [30, 56, 25], [10, 20], [33], [40]]
New List [[10, 20], [30, 56, 25], [33], [40]]

Flowchart:

For more Practice: Solve these Related Problems:

• Write a Python program to remove duplicate lists regardless of order.
• Write a Python program to remove lists that contain duplicate values within themselves.
• Write a Python program to remove duplicate lists based on a specific index value.
• Write a Python program to remove duplicate lists where at least one element is repeated.

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• Python Data Type List Exercises Home ↩
• Python Exercises Home ↩

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