How Do You Determine if a Variable Represents an Integer in Python?

Determining if a Variable Represents an Integer

In programming, verifying the type of a variable can be crucial. This article explores how to ascertain whether a variable holds an integer value.

The isinstance() Method

Python provides the isinstance() function to inspect the type of a variable. To determine if a variable represents an integer, use:

isinstance(variable, int)

In Python 2.x, long integers are also considered integers, so you might need:

isinstance(variable, (int, long))

Why Avoid the type Function?

Contrary to the isinstance() method, the type() function does not accommodate class inheritance and polymorphism. As a result, if you subclass int, your new class would not be recognized as an integer by type().

The Forgiveness Approach

A common practice in Python is to anticipate the possibility of non-integer values rather than explicitly checking for them. This approach involves attempting to perform integer operations and handling any resulting exceptions:

try:
    variable += 1
except TypeError:
    ...

Abstract Base Classes: A Robust Solution

For more precise control, abstract base classes can enforce the presence of specific methods in an object. This enables you to verify the availability of operations like addition or multiplication, offering a more tailored approach for integer validation.

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