Home / Questions / 401660
Accepted
Candid Moe
Asked: 2021-10-28 05:22:59 +0800 CST 2021-10-28 05:22:59 +0800 CST

Error: xxx Object is not callable. What does it mean and how do I fix it?

  • 772

I have this program

a = 5
print("valor=", 5*a())

when executing it throws me this error:

Traceback (most recent call last):
  File "/home/candid/PycharmProjects/scrapper2/scrapper.py", line 2, in <module>
    print("valor=", 5*a())
TypeError: 'int' object is not callable

and I don't understand what I'm doing wrong.

python

1 Answers

  1. Best Answer

    Short explanation: Use []to access an element of a collection. Use ()to call a function.

    In Python, Xany object is callable when it can be used as a function call X(), possibly receiving parameters and returning something.

    A numeric variable is not callable . It is not something that is defined; there is no code to execute behind that value.

    Strings, lists, tuples, and dictionaries are also not callable , for the same reason.

    Typically this error occurs when they are used ()instead of []to access an element within a string, list, tuple, or dictionary.

    The following uses are correct (with []):

    nombre = "Jacinto Perez"
lista = ["azul", "rojo"]
tupla = ("pollo", "gato")
dic = {"Mac": 1, "PC": 2}

print(nombre[2])
print(lista[1])
print(tupla[0])
print(dic["Mac"])

    produces

    c
rojo
pollo
1

    But if you change them []to()

    print(nombre(2))
print(lista(1))
print(tupla(0))
print(dic("Mac"))

    throws error:

      File "/home/candid/PycharmProjects/scrapper2/scrapper.py", line 6, in <module>
    print(nombre(2))
TypeError: 'str' object is not callable

    What objects are callable ?

    Functions, generators, and any objects that define the magic method are callable__call__ .

    Example: we have a class Cliente, which stores name and balance:

    class Cliente:
    def __init__(self, nombre, saldo):
        self.nombre = nombre
        self.saldo = saldo

    we can create a client with

    cliente = Cliente("Jacinto Perez", 1000)

    but we can't say

    print(cliente())

    then the error appears

    TypeError: 'Cliente' object is not callable

    which says that the class Clienteis not callable , and therefore no object of that class is.

    To make it callable , we define the method __call__, with the following signature

    def __call__(self, *args, **kwargs):

    Note that you always have to define it with those arguments, even if they are not used in a particular implementation. Otherwise, Python does not consider the class callable .

    What is this method supposed to do? Whatever is appropriate to our application; For example, in a banking application, the most used method may be the customer balance query:

    So, we redefine the class Cliente:

    class Cliente:
    def __init__(self, nombre, saldo):
        self.nombre = nombre
        self.saldo = saldo

    def __call__(self, self, *args, **kwargs):
        return self.saldo


cliente = Cliente("Jacinto Perez", "[email protected]", "912341234")
print(cliente())

    now print the customer balance.

    Note: This example is usually solved by defining a query function

    def saldo(self):
    return self.saldo

    but what's up! You have to give a simple example.

    Implementing __call__is more of a matter of convenience when there is a particular method that you use frequently and you want to save yourself having to type the method name over and over again.

    How to know if an object is callable ?

    There is the function callable(objeto)that returns Trueif the object is callable and Falseotherwise:

    saldo = 1000
nom = "Jacinto"
cliente = Cliente(nom, saldo)

callable(saldo) # Retorna False
callable(nom) # Retorna False
callable(cliente) # Retorna True
    • 6