How to Check if Variable Is Integer Python

1. Use the isinstance() Method to Check if an Object Is an int Type in Python
2. Use the int() Method to Check if an Object Is an int Type in Python
3. Use the float.is_integer() Method to Check if an Object Is an int Type in Python

In Python, we have different datatypes when we deal with numbers. These are the int, float, and complex datatypes.

The int datatype is used to represent integers. In this tutorial, we will discuss how to check if a variable is int or not.

In Python, we usually check the type() function to return the type of the object. For example,

x = 10
print(type(x))
print(type(x) == int)

Output:

<class 'int'>
True

This method may work normally, but it blocks all flexibility of polymorphism. For example, if we subclass an object as int and expect it to register as int, this might fail with the type() function.

The following code demonstrates this.

class def_int(int):
    pass


x = def_int(0)
print(type(x))
print(type(x) == int)

Output:

<class '__main__.def_int'>
False

Use the isinstance() Method to Check if an Object Is an int Type in Python

It is therefore encouraged to use the isinstance() function over the traditional type(). The isinstance() function is used to check whether an object belongs to the specified subclass. The following code snippet will explain how we can use it to check for int objects.

y = 10


class def_int(int):
    pass


x = def_int(0)
print(isinstance(y, int))
print(isinstance(x, int))

Output:

True
True

It is recommended to use the abstract base class numbers.Integral, instead of the concrete int class. In this way, we can check for int, long, and even the user-defined methods that can act as an integer.

Use the int() Method to Check if an Object Is an int Type in Python

We can create a simple logic also to achieve this using the int function. For an object to be int, it should be equal to the value returned by the int() function when this object is passed to it. The following code demonstrates this.

x = 10.05

if int(x) == x:
    print("True")
else:
    print("False")

Output:

False

This method will return a Type-error when worked with complex objects.

Use the float.is_integer() Method to Check if an Object Is an int Type in Python

This method works only for float objects. It checks if the value in a float object is an integer or not. For example,

x = 10.0
print(float.is_integer(x))

Output:

True