Object identity tells separate Python objects apart, even when they contain the same data. A variable name binds to an object, and the name can later bind to another object. section 4.2
Use identity to read what your code actually created:
- Calling id(object) produces a unique identity for that object while it exists. section 4.2
- Creating a new Circle on each loop produces separate objects, even when every radius is 1. section 32.2
- Adding one Circle repeatedly stores references to the same object, so the printed location repeats. section 32.2
Compare two identities
c = 1 id(c) c = 2 id(c) The name c stays the same, but reassignment gives it a different object, so the two id() results differ. The same check helps distinguish a stack containing several separately created circles from one containing the same circle five times. section 4.2 section 32.2
c = 1 id(c) c = 2 id(c)
Run the short reassignment example and compare the identities printed before and after c receives a new value. section 4.2
