Lesson 01 · 10 min

Indentation, names, types as a habit

There are no block braces. A block is defined by indentation. You don't write the type up front, but the value still has one.

In Python a block isn't in { }. After : comes a new line and a 4-space indent. Mix tabs and spaces and you get an error, not "well, it almost works". A variable name doesn't carry a type: n = 1 can later become n = "one". The value has a type, not the box.

A branch

You can ask about this rule«No declaring in advance»

# is a comment to the end of the line.
None means "nothing"; don't confuse it with 0 and "". In a condition None is false.
A string and a number don't add silently: "n=" + 1 fails. You need str(1) or an f-string f"n={n}".

You can ask about this point«Lesson summary»

Check

Lock it in before you move on

1. How is the body of an if marked in Python?
2. What does "n=" + 1 do?
3. None is closer to

PracticeSolve the lesson tasksA few short tasks in the editor. Check your code right away and see where it goes wrong.Start practice