Names and Objects
Interactive lab
Try it: Names and Objects
How Python variables are names bound to objects: assignment never copies, mutating a list is seen through every name that points at it, and ints are replaced rather than changed.
How it works
- name = object binds a name; b = a makes b point at the same object.
- Mutating a list (append, +=) changes the one shared object.
- a = a + [x] and y = y + 1 create NEW objects and re-point one name.
- Passing a list to a function passes the reference, so the function can change it.
Default run (7 steps): Two names, one list. Every name is a label that points at an object. … Printed: [1, 2, 3] / True
Simplified: Six fixed scripts on a tiny heap; you choose the values. Object numbers are illustrative, not real id() values.
Educational simulation
Loading the simulation…