__repr__ method
The __repr__ special method is called by the repr built-in to get the string representation of the object for inspection.
Without a custom __repr__, Python’s console would display a Vector instance <Vector object at 0x10e100070>.
The string returned by __repr__ should be unambiguous and, if possible, match the source code necessary to re-create the represented object. E.g. Vector(1, 2) instead of Vector('1', '2'), if parameters should be integers, and not strings.
For that, the good practice is to use !r conversion flag:
class Vector:
def __init__(self, x=0, y=0):
self.x = x
self.y = y
def __repr__(self):
return f'Vector({self.x!r}, {self.y!r})'__repr__ implementation should be prioritized over __str__.
__str__ method
In contrast, __str__ is called by the str() built-in and implicitly used by the print function. It should return a string suitable for display to end users.
Sometimes the string returned by __repr__ is already user-friendly. In that case you don’t need to code __str__ because the implementation inherited from the object class calls __repr__ as a fallback. But not vice versa.
__repr__ vs __str__
https://stackoverflow.com/questions/1436703/what-is-the-difference-between-str-and-repr