Python2和Python3的metaclass使用

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代码实现通过元类将类对象和实例的属性全部大写。

Python2：

def upper_attr(futer_class_name, future_class_parent, futuer_class_attr):    attrs = ((name, value) for name, value in futuer_class_attr.item() if name.startswith('__'))    uppercase_attr = dict((name.upper(),value) for name, value in attrs)    return type(futer_class_name, future_class_parent, uppercase_attr)__metaclass__ = upper_attrclass Foo(object):    bar = 'bip'print(hasattr(Foo, 'bar'))print(hasattr(Foo, 'BAR'))f = Foo()print(hasattr(f,'bar'))print(hasattr(f,'BAR'))

Python 3：

def upper_attr(future_class_name, future_class_parents, future_class_attr):    attrs = ((name, value) for name, value in future_class_attr.items() if not name.startswith('__'))    uppercase_attr = dict((name.upper(), value) for name, value in attrs)    return type(future_class_name, future_class_parents, uppercase_attr)class Foo(metaclass = upper_attr):    bar = 'bip'print(hasattr(Foo, 'bar'))print(hasattr(Foo, 'BAR'))f = Foo()print(hasattr(f,'bar'))print(hasattr(f,'BAR'))

Python2 部分代码详细请看深刻理解Python中的元类(metaclass)

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