Recursion Basics

Concepts: pyRecursion

Recursion is when a function calls itself. This technique elegantly solves problems that can be broken into smaller versions of the same problem. While it might seem strange at first, recursion is natural for tree traversal, nested data processing, and divide-and-conquer algorithms. Once you understand it, certain problems become almost trivial to solve. Data engineers encounter recursion when traversing nested JSON from APIs, processing file system hierarchies, flattening deeply nested structures, and implementing certain algorithms. Parsing a JSON response with unknown nesting depth? Recursion handles it naturally. Walking a directory tree to find all files matching a pattern? Recursion is the obvious solution. Recursion is also a favorite topic in technical interviews because it tests y