How Can I Efficiently Deduplicate a List of Lists While Maintaining Order?

Efficiently Removing Duplicates from a List of Lists

Given a list of lists, the goal is to eliminate duplicate elements while preserving order. While converting lists to tuples to leverage sets would be straightforward, it's inefficient.

Utilizing itertools.groupby()

itertools offers a remarkable solution:

import itertools

k.sort()
list(k for k,_ in itertools.groupby(k))

This approach excels by:

• Sorting the lists to align duplicates.
• Grouping the lists based on elements, with each group represented by its first occurrence.
• Converting the group keys (duplicates removed) back to a list.

Benchmark Analysis

Extensive benchmarking reveals that "groupby" generally outperforms other methods for large input lists. However, for tiny lists with few duplicates, the "loop in" approach might be slightly faster.

Optimizing for Specific Applications

When performance is paramount, consider:

• Heuristic Input Analysis: Detecting input characteristics to guide algorithm selection.
• Alternative Data Structures: Assessing if a set of tuples would be a more suitable representation for the data.
• Probabilistic Modeling: Analyzing the distribution of duplicates to optimize performance measures.

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