How to Dry Run Python Code: Step-by-Step Method

List every variable, parameter, and relevant builtin. Note which objects are mutable. Mark global versus local scope before you execute line one.

Never skip lines. For compound statements, expand: a for loop becomes many lines; a list comprehension becomes an explicit loop in your scratch work.

Maintain an output buffer. print adds text exactly - including spaces, commas as spaces between items, and trailing newlines unless end= changes it.

Check empty inputs, single-element collections, and off-by-one bounds. In interviews, narrate your table; silence reads as guessing. Practice the full method on challenge.html with timed mode enabled.