6. Vectorization

Vectorization is the art of operating on entire arrays at once, rather than looping through individual elements. This powerful programming paradigm encourages you to “think in arrays,” much like you would in a math class. The result is code that’s not only more compact and readable but also significantly faster, as it allows Julia to use highly-optimized, low-level routines for computation.

This chapter provides a comprehensive toolkit for writing vectorized code. We’ll begin by mastering array comprehensions for elegant array creation. Next, we’ll explore a suite of built-in functions for summarizing, transforming, and querying data, including how to apply them along specific dimensions. You’ll then learn the indispensable technique of logical indexing to filter data with boolean masks. To see these concepts in action, we’ll conclude by refactoring code from our previous examples, transforming them into remarkably concise and efficient solutions.