Python variable and immutable types

Length summarize the basics of Python, write a write not easy to forget

* Python data types can be divided into variable and immutable type two categories

Mutable type: list, dictionary

Immutable types: Numeric, character, tuple

* When an immutable type is assigned, a new immutable object is created, and a variable pointing to the original immutable object points to the new immutable object, which loses the variable that points to it, and the immutable object is recycled if no new variable points to it.

eg

1 i=12 i+=13i4 2

Instead of actually adding 1 to the original int object, the i+=1 here re-creates a 2 object and references I to this object

Python variable and immutable types