Python: ___ () vs ___ str__()

 

class Vector(object):

    def __init__(self, x=0, y=0):
        self.x = x
        self.y = y

    def __repr__(self):
        return 'Vector(%r, %r)-repr' % (self.x, self.y)

    def __abs__(self):
        return 'Vector(%r, %r)-str' % (self.x, self.y)

Result

Comment

The method of

  • /repr__() is provided by the object class, and all Python classes are subclasses of the object class, so all Python objects have the method of ___. So if you need to concatenate any object with a string, you can call the method with ___ first to turn the object into a string and then concatenate the strings together.
  • repr__() is special because it is a “self-describing” method, usually with the following scenario: when the developer prints the object directly, the system prints out the “self-describing” message with the object, telling the outside world the state the object has . __repr__() the method provided by the
  • object always returns the “ class name +object at + memory address ” with the object implementation class. This return value does not really implement the ‘self-describing’ function, so if the user needs to custom class to do it, he/she must rewrite the method with repr__().
  • is generally more readable with succinct __str__(), and the return result of each __repr__() is more accurate and more appropriate for the developer. </ li>
  • for developers, in the implementation class, suggested rewriting __repr__ () function </ span> </ strong>!


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