Left Join

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

Domain

Python

Difficulty

medium

Seniority

L4

Problem

Given two lists of dicts (left, right) and a shared key name, left-join the lists: for each left record, find the matching right record (the first one whose key matches) and merge its fields into the left record. If no right-side match exists, keep the left record as-is with no extra keys. Return the list.

Summary

Keep the left side. Match what you can.

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