Printing Objects

Introduction to __str__ method

The print method takes any number of arguments, converts each argument into a string by calling its __str__ method, and prints them. As with __init__, that’s two underscores before and after the name.

All classes have a __str__ method inherited from object. It is a good idea to override this method. If you don’t, your objects will print something like this:

<__main__.Friend object at 0x1064728d0>

In the case of a Friend object, your method might look something like this:

def __str__(self):
 return self.name + "'s age is " + str(self.age)

print(meg) would result in Margaret's age is 25.

In the above example, Margret’s age is an integer, and we can’t add an integer to a string. Therefore, we had to explicitly convert her age to a string by calling the function str(self.age). Once you’ve defined the __str__ method in your class, you can call the str function on objects of that class, by saying str(meg) for example.

Technical note: Yes, you define the __str__ method, then use it by calling the str function.

You can observe this in the example below: