I&#x27;ll hold my hands up and say I did have a knee-jerk reaction to the criticism but then I remembered when I started learning Lisp.<p>I did often wonder where the arrays, hashmaps and other data structures were. I remember I had my own practice problems that involved random access so a vector would have been more efficient than a list.<p>In fairness, I think you either will be far enough on your travels with other languages to intuit that Lisp implementations do have these primitives (&quot;surely not? Ah, lo and behold, racket has a nice vector interface. Not sure about CL&#x27;s hashmap interface...&quot; and so on) or you will be so far on your travels with lisp to understand why you need this that you already know.<p>I don&#x27;t think I would direct a complete beginner to programmer to this page.