How a Computer Follows Instructions

A program is a sequence of instructions a computer follows exactly, with no sense of what you meant. Values are the numbers, text, and lists it works with; variables give them names; control flow decides which instruction runs next, through conditions and loops; functions package steps behind a name so they can be reused and tested. Every other software page on this site builds on these four ideas.

#>programs_essentials

Programs Essentials

A guided first language

MDN's JavaScript guide, from values to functions, runnable in any browser.

mdn: JavaScript guide

A complete first course

Harvard's CS50, free, with problem sets that build real habits.

cs50

The analyst's first language

The official Python tutorial, the usual starting point for data work.

python: tutorial