Videos
Python for AP CS Principles
Pick a topic to watch.
15 video lessons
2:07
Lesson 1
What computing is
A program is a set of instructions a computer follows, and almost every one of them has this shape. Input: data goes in — a number you type, a tap, a file.…
2:21
Lesson 2
Bits and binary
A bit is one digit that is either zero or one, and computers store everything — numbers, text, pictures, music — as bits. The reason is physical. A chip is…
1:44
Lesson 3
Data compression
Data costs space to store and time to send, so we compress it — and there are two kinds. Lossless makes a file smaller while keeping every single bit. Follow…
2:11
Lesson 4
Variables and expressions
A variable stores a value so you can use it later, and the equals sign does not mean equals — it means "store into". Which is why the second line here confuses…
2:08
Lesson 5
Lists and data abstraction
A program often needs many values at once — a whole class of scores. One variable per value gets messy fast, and it does not scale at all. A list holds many…
2:09
Lesson 6
Selection
Selection means the program picks what to do based on a condition. And an if-elif-else is a chain, not three separate questions — watch what happens with the…
2:11
Lesson 7
Iteration
Iteration means doing the same steps again and again, which is how a little code does a lot of work. The commonest loop counts with range. And here is the…
1:49
Lesson 8
Procedures and abstraction
A procedure is a named block of code you can use again and again. In Python you make one with def, then a name, then brackets, and the code goes indented…
2:08
Lesson 9
Algorithms: searching
An algorithm is a clear, finite list of steps that solves a problem, and searching is the classic one: find where a value sits in a list. Linear search checks…
2:02
Lesson 10
Randomness and simulation
Some programs need chance — games, experiments, models of the real world. The random tools live in a module, so you write import random at the top. Then…
1:55
Lesson 11
Algorithmic efficiency
Two programs can both be correct and still take wildly different amounts of time, so we need a way to compare them. We measure an algorithm by how many steps…
2:15
Lesson 12
The Internet and how data travels
The Internet is an enormous network of computers joined together, and no single one of them is in charge. When you send something across it, the data does not…
2:11
Lesson 13
Parallel and distributed computing
Most simple programs are sequential: step one finishes before step two starts. Easy to follow, but slow for a big job — look at how far that top row runs.…
2:23
Lesson 14
Impact of computing
Computing touches almost every part of life, and the same tool brings benefits and harms — not one or the other, both at once. Social media lets you stay in…
2:14
Lesson 15
The Create Performance Task
The Create Performance Task is a small program you design and build yourself, and it has a short list of requirements. A list, or another collection, that…