Python __repr__() magic method Syntax
Syntax: object.__repr__()
- object: The object whose printable representation is to be returned.
Return: Simple string representation of the passed object.
Python __repr__() method Example
In this example, we define a GFG class with three instance variables f_name, m_name, and l_name representing the first, middle, and last name of a person, respectively. The __repr__() method is defined to return a string representation of the instance in a format that can be used to recreate the object.
Python3
class GFG: def __init__(self, f_name, m_name, l_name): self.f_name = f_name self.m_name = m_name self.l_name = l_name def __repr__(self): return f'GFG("{self.f_name}","{self.m_name}","{self.l_name}")'gfg = GFG("Geeks", "For", "Geeks")print(repr(gfg)) |
Output:
GFG("Geeks","For","Geeks")
Difference between __str__() and __repr__() magic method
In this example, we define a GFG class with one instance variable name representing the name of a person. The __str__() method is defined to return a human-readable string representation of the instance, while the __repr__() method is defined to return a string representation of the instance that can be used to recreate the object.
When we create an instance of the GFG class and call __str__() or __repr__() directly on the object, the respective method is called and returns a string that represents the object.
Python3
class GFG: def __init__(self, name): self.name = name def __str__(self): return f'Name is {self.name}' def __repr__(self): return f'GFG(name={self.name})'obj = GFG('w3wiki')print(obj.__str__())print(obj.__repr__()) |
Output:
Name is w3wiki GFG(name=w3wiki)
You can also read str() vs repr() in Python.
__str__() and __repr__() Examples Using a Built-In Class
In this example, we define a subclass of tuple called MyTuple that overrides the __str__() and __repr__() methods. When we call Python str() or Python repr() on an instance of MyTuple, the custom __str__() and __repr__() methods are called, respectively.
Python3
class MyTuple(tuple): def __str__(self): return f"MyTuple({super().__str__()})" def __repr__(self): return f"MyTuple({super().__repr__()})"mt = MyTuple((1,2,3))print(mt.__repr__())print(mt.__str__()) |
Output:
MyTuple((1, 2, 3)) MyTuple(MyTuple((1, 2, 3)))
__str__() and __repr__() Examples Using a New Class
In this example, we define a Book class with three instance variables title, author, and pages representing the title, author, and number of pages of a book, respectively. The __str__() method is defined to return a string representation of the instance in a human-readable format, while the __repr__() method is defined to return a string representation of the instance that can be used to recreate the object.
When we create an instance of the Book class and call str() on it, the __str__() method is called and returns a human-readable string that represents the object. When we call repr() on it, the __repr__() method is called and returns a string that represents the object in a way that it can be recreated.
Python3
class Book: def __init__(self, title, author, pages): self.title = title self.author = author self.pages = pages def __str__(self): return f"{self.title} by {self.author}, {self.pages} pages" def __repr__(self): return f"Book('{self.title}', '{self.author}', {self.pages})"book1 = Book("The Hitchhiker's Guide to the Galaxy", "Douglas Adams", 224)print("Using str(): ", str(book1))print("Using repr(): ", repr(book1)) |
Output:
Using str(): The Hitchhiker's Guide to the Galaxy by Douglas Adams, 224 pages
Using repr(): Book('The Hitchhiker's Guide to the Galaxy', 'Douglas Adams', 224)
Practical usage of __repr__() magic method
This code creates a Color class with an __init__() method that takes a suffix parameter and sets an instance variable self. suffix to that value. It also sets another instance variable self. title to a string that includes the suffix. Finally, it defines an __repr__() method that returns a string representation of the object.
Python3
class Color: def __init__(self, suffix): self.suffix = suffix self.title = f"Golden {suffix}" def __repr__(self): return f"Color('{self.suffix}')"c1 = Color("Yellow")# create another object with same params as c1# using eval() on repr()c2 = eval(repr(c1))print("c1.title:", c1.title)print("c2.title:", c2.title) |
Output:
c1.title: Golden Yellow c2.title: Golden Yellow
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