List of objects in Python

Question

I’m doing a function that returns an object list. Snippet from the code:

def guarda_word(lista_palavras,lista_objeto,indice):

    for i in lista_palavras:
        if bool(lista_objeto) == True: # a list de objeto esta vazia
            i = PalavraIndices(i)
            i.add_item(indice,1)
            lista_objeto.append(i)
        elif i not in lista_objeto: # o elemento da lista de palavras ainda nao tem um objeto
            i = PalavraIndices(i)
            i.add_item(indice,1)
            lista_objeto.append(i)
        else:
            i.add_item(indice,1)
    return lista_objeto

lista_objeto = guarda_word(palavras_A,lista_objeto,'arquivoA')

print(lista_objeto)

The problem is, when I print this list of objects on the screen. it comes out this way:

[<__main__.PalavraIndices object at 0x005E6970>, <__main__.PalavraIndices 
object at 0x005E6990>, <__main__.PalavraIndices object at 0x005E69B0>, 
<__main__.PalavraIndices object at 0x005E69D0>, <__main__.PalavraIndices 
object at 0x005E69F0>, <__main__.PalavraIndices object at 0x005E6A30>, 
<__main__.PalavraIndices object at 0x005E6A50>, <__main__.PalavraIndices 
object at 0x005E6A70>, <__main__.PalavraIndices object at 0x005E6A90>, 
<__main__.PalavraIndices object at 0x005E6A10>, <__main__.PalavraIndices 
object at 0x005E6AB0>, <__main__.PalavraIndices object at 0x005E6AD0>, 
<__main__.PalavraIndices object at 0x005E6AF0>]

Does anyone know why the name of each object in this list is not just appearing?

Answer 1

You must add a method __repr__(self) on the instantiated object, which will return a string as you want it to be displayed on screen.

Behold this reply for more information.

def __repr__(self):
     return str(self.__dict__)

Answer 2

If the goal is just to show the class name, you can do so:

class Foo:
    pass
print(Foo().__class__.__name__) # Foo

DEMONSTRATION

But if you want something more personalized for each object (class instance) depending on the entries you can do for example:

class Foo:
    def __init__(self, bar):
        self.bar = bar
    def __repr__(self):
        return 'Class {} em que na sua variável de instância bar é {}'.format(self.__class__.__name__, self.bar)

print(Foo('hey')) # Class Foo em que na sua variável de instância bar é hey
print(Foo('lol')) # Class Foo em que na sua variável de instância bar é lol
print(Foo('bar')) # Class Foo em que na sua variável de instância bar é bar

DEMONSTRATION

But if you don’t declare this method, or in this case __str__(self), the output for this is just this 'general descriptive'.

There are some examples of classes that are used very often that work exactly like this:

from decimal import Decimal

print(Decimal('10.5')) # 10.5
print(Decimal('21.2')) # 21.2

DEMONSTRATION