Effective Python

原文摘录  · · · · · · 

• class LazyDB(object): def __init__(self): self.exists = 5 def __getattr__(self, name): value = 'Value for {}'.format(name) print 'hhhhh' setattr(self, name, value) return value class LoggingLazyDB(LazyDB): def __getattr__(self, name): print 'Called __getattr__{}'.format(name) return super().__getattr__(name) data = LoggingLazyDB() print 'foo exists: {}'.format(hasattr(data, 'foo')) >>> Called __getattr__foo >>> foo exists: False (查看原文)

  sindwerra 2019-01-29 20:58:38