Why Python Performs Floating-Point Division for Integer Division

In recent versions of Python (3 onwards), integer division (dividing two integers) yields a float instead of an integer. This behavior differs from earlier versions, which favored integer results for integer operands.

Consider the following division in Python 3:

>>> 2 / 2
1.0

This surprising result may cause confusion, especially if you're accustomed to older Python versions.

The Reason Behind the Change

The rationale for this change is documented in PEP-238: Changing the Division Operator. The proposal aimed to:

• Introduce unambiguous floor division, denoted by the // operator.
• Eliminate the potential for unintended type conversions and round-tripping errors with mixed-type operands.

Implications for Your Code

This change has several implications for your Python code:

• If you need integer division (rounded towards zero), use the // operator explicitly.
• If you expect a float result, casting is unnecessary.
• For maximum readability, consider using the // and / operators judiciously to convey your intent clearly.

Example:

# Explicit floor division
result = 2 // 2  # 1

# Float division
result = 2 / 2  # 1.0

Additional Resources

• [PEP-238: Changing the Division Operator](https://www.python.org/dev/peps/pep-0238/)