MEPX
Chapter 4 of 15All chapters
  1. 1Introduction
  2. 2Syntax and indentation
  3. 3Variables
  4. 4Data types
  5. 5Numbers and maths
  6. 6Strings
  7. 7Lists
  8. 8Tuples and sets
  9. 9Dictionaries
  10. 10Conditions
  11. 11Loops
  12. 12Functions
  13. 13Classes and objects
  14. 14File handling
  15. 15Modules and packages

Chapter 4 of 15

Data types

The built-in types and how to check one.

The everyday types

Numbers come as int and float, text as str, truth values as bool, and nothing as None. The containers are list, tuple, dict and set.

  • type(x) returns the type, and isinstance(x, int) is the check to prefer in code.
  • bool is a subclass of int, so True behaves as 1 in arithmetic.

Converting

Each type doubles as a converter: int("7") gives 7, str(7) gives "7", and list("abc") gives a list of characters. A conversion that cannot work raises ValueError rather than guessing.