Read Both Ways

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

Domain

Python

Difficulty

easy

Seniority

junior

Problem

We sweep production records for placeholder identifiers that QA seeds as values reading the same forwards and backwards, so they are easy to spot and purge later. Scan a batch of `tokens` and return the ones that still read the same in both directions once you ignore case and any character that is not a letter or digit, keeping them in the order they appeared. A token with no letters or digits at all does not count.

Summary

Placeholders hide in plain sight. The symmetric ones give themselves away.

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