Lists, dicts & comprehensions
Almost every script you'll write holds a collection of things: a set of servers, a
table of counts, a batch of rows. Two built-in structures carry most of that work, and a
one-line idiom builds new ones from old. Your main.py builds up across the steps.
pythonautomationdata-structures
Interview prep
Reaching for a comprehension instead of a manual loop-and-append is a quick fluency signal.
When would you use a list comprehension over a for loop?
When you're building a new list by transforming or filtering an existing iterable — [f(x) for x in items if cond(x)]. It's more concise and usually faster than initializing an empty list and appending in a loop. For side effects (printing, writing) or complex logic, a plain loop is clearer.