The Ones That Come Back

A easy Python interview practice problem on DataDriven. Write and execute real python code with instant feedback.

Domain

Python

Difficulty

easy

Seniority

L3

Problem

A data-quality check on an event export turned up a column of integer `ids` that should be unique but isn't. Return the id values that appear more than once, from smallest to largest.

Summary

In a column that promised uniqueness, some values kept their seat. Name them.

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