How Can I Determine if a Variable is an Integer in Python?

Checking Variable Type: Integers

When working with variables in Python, it may be essential to ascertain whether a specific variable holds an integer value. To achieve this, you can capitalize on Python's powerful isinstance() function.

Using isinstance()

To determine if a variable is an integer, utilize isinstance() as follows:

isinstance(<var>, int)

For instance:

my_var = 10
if isinstance(my_var, int):
    print("my_var is an integer.")

In Python 2.x, long integers coexisted with standard integers, so you'll need to check using:

isinstance(<var>, (int, long))

Avoiding type()

Refrain from using type() to perform this check. Unlike isinstance(), type() doesn't account for object polymorphism in Python. This shortcoming stems from type() exclusively considering the direct type of an object, whereas isinstance() properly handles inheritance and polymorphism.

"Ask Forgiveness, Not Permission" Mentality

In the Python world, a common approach advocates "asking for forgiveness rather than permission." Instead of checking variable types upfront, assume integer behavior and handle TypeError exceptions as needed. This approach simplifies code but sacrifices some safety.

Abstract Base Classes

For a more robust solution, consider employing abstract base classes (ABCs) to enforce specific object properties and provide finer-grained control over object behavior.

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