Python Data Types

Study Notes

str: strings, e.g. "hello", 'hello', etc. (immutable)
- Can be indexed and sliced like lists
- Supports string methods like upper(), lower(), etc.
list: ordered collection of items, e.g. [1, 2, 3], ["a", "b", "c"], etc. (mutable)
- Can be indexed and sliced
- Supports list methods like append(), extend(), etc.
tuple: ordered, immutable collection of items, e.g. (1, 2, 3), ("a", "b", "c"), etc.

dict: unordered collection of key-value pairs, e.g. {"name": "John", "age": 30}, etc. (mutable)
- Can be indexed by key
- Supports dictionary methods like keys(), values(), etc.

set: unordered collection of unique items, e.g. {1, 2, 3}, {"a", "b", "c"}, etc. (mutable)
- Supports set methods like union(), intersection(), etc.
frozenset: unordered, immutable collection of unique items, e.g. frozenset({1, 2, 3}), etc.

bytes: sequence of integers in the range 0 <= x < 256, e.g. b"hello", etc.
bytearray: mutable sequence of integers in the range 0 <= x < 256, e.g. bytearray(b"hello"), etc.

There are three sequence types: str, list, and tuple.
str represents strings, such as "hello" and 'hello', which are immutable.
str can be indexed and sliced like lists and supports string methods like upper() and lower().
list represents ordered collections of items, such as [1, 2, 3] and ["a", "b", "c"], which are mutable.
list can be indexed and sliced and supports list methods like append() and extend().
tuple represents ordered, immutable collections of items, such as (1, 2, 3) and ("a", "b", "c").

dict represents unordered collections of key-value pairs, such as {"name": "John", "age": 30}, which are mutable.
dict can be indexed by key and supports dictionary methods like keys() and values().

There are two set types: set and frozenset.
set represents unordered collections of unique items, such as {1, 2, 3} and {"a", "b", "c"}, which are mutable.
set supports set methods like union() and intersection().
frozenset represents unordered, immutable collections of unique items, such as frozenset({1, 2, 3}).