P01PythonBeginnerInterpret8 min
Remove Duplicates While Preserving Order
Return unique event labels without changing the order in which users first saw them.
#lists#sets#data quality
Scenario
A product analytics export contains repeated event names for a customer session. Your report needs one row per event type, ordered by first occurrence.
Problem statement
Given a list of values, remove duplicates while preserving the original order. Do not sort the input.
Your Task
- Choose a data structure for fast membership checks.
- Keep the first occurrence of each value.
- Explain why converting directly to a set is not sufficient for this task.
Input
events = ['view', 'add_to_cart', 'view', 'checkout', 'add_to_cart']Related Concepts
Python setsListsData deduplication
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