Data Classes

How Python punishes us for trying to do right when following principles for object-oriented design and what new features are coming to 3.7 that will make our lives easier.

Lighting talk at December CamPUG meeting

Transcript

1. Jan Chwiejczak iamjanhak How Python encourages bad habits
2. How Python punishes good OOD goo.gl/QJDG22
3. How Python punishes good OOD  Python multi paradigm programming language goo.gl/QJDG22
4. How Python punishes good OOD  Python multi paradigm programming language  However, most serious projects have a strong OOD structure goo.gl/QJDG22
5. How Python punishes good OOD  Python multi paradigm programming language  However, most serious projects have a strong OOD structure  Make lots of small self contained classes that do one thing and do it well goo.gl/QJDG22
6. IT IS QUITE TEDIUS MOST LIKELY YOU WON’T BOTHER
7. We leverage Python strengths goo.gl/QJDG22
8. We leverage Python strengths  name, host = … goo.gl/QJDG22
9. We leverage Python strengths  name, host = …  [(name, host, port, arm_type)] = … goo.gl/QJDG22
10. We leverage Python strengths  name, host = …  [(name, host, port, arm_type)] = …  self.params[‘arm_pool’][name][3][INSTRUMENT] goo.gl/QJDG22
11. We leverage Python strengths  name, host = …  [(name, host, port, arm_type)] = …  self.params[‘arm_pool’][name][3][INSTRUMENT] goo.gl/QJDG22
12. www.github.com/janhak/bytecode CLASSES SEEM LIKE A BETTER IDEA!
13. Starts well goo.gl/QJDG22
14. Starts well class Arm: goo.gl/QJDG22
15. Starts well class Arm: class Arm: def __init__(self, name, host, port, arm_type): ... goo.gl/QJDG22
16. Starts well class Arm: class Arm: def __init__(self, name, host, port, arm_type): ... class Arm: def __init__(self, name, host, port, arm_type): self.name = name self.host = host self.port = port self.arm_type = arm_type goo.gl/QJDG22
17. This is getting tedious class Arm: def __init__(self, name, host, port, arm_type): self.name = name self.host = host self.port = port self.arm_type = arm_type def __repr__(self): return self.__class__.__name__ + '(name={}, host={}, port={}, arm_type={})'.format( self.name, self.host, self.port, self.arm_type) goo.gl/QJDG22
18. How about comparison class Arm: ... def __eq__(self, other): if not isinstance(other, self.__class__): return NotImplemented return (( self.name, self.host, self.port, self.arm_type) == (other.name, other.host, other.port, other.arm_type)) goo.gl/QJDG22
19. Named Tuple from collections import namedtuple Arm = namedtuple('Arm', ['name', 'host', 'port', 'arm_type']) goo.gl/QJDG22
20. ENTER DATA CLASSES
21. goo.gl/QJDG22