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为自己定义每个python类添加__repr__和__str__

 3 years ago
source link: https://segmentfault.com/a/1190000039855020
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为自己定义每个python类添加__repr__和__str__

发布于 10 分钟前

在类定义里,使用__str__和__repr__双下划线能够自行控制类中的字符串转换.

class Car:
    def __init__(self,color,mileage):
        self.color = color
        self.mileage = mileage
        
    def __repr__(self):
        return (f'{self.__class__.__name__}('
                f'{self.color!r},{self.mileage!r})')

    def __str__(self):
        return f'a {self.color} car'
    
    
my_car = Car('blue',929192)
print(my_car)   
#=> a blue car
#=> 如果不定义__str__,则结果为 Car('blue',929192)
  • __str__ 的结果应该是可读的.
  • __repr__ 的结果应该是无歧义的,方便开发人员调试.
  • 如果没有定义__str__ , 则会默认调用__repr__

Flutter 写的app, 需要源码可以私信~~

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