Why Do Leading Zeros in Python Integers Result in Unexpected Behavior?

Understanding Prefix Zeros in Python Integers

In Python, when numbers are entered with a leading zero, they behave differently from regular integers. This is because these numbers are interpreted as octal numbers (base-8).

An octal number consists of digits ranging from 0 to 7. When Python encounters a number starting with 0, it automatically converts it to octal. This can lead to unexpected results, as the numerical value will differ from the expected decimal representation.

Examples in Python 2 (Old Format)

• 011: This number converts to 1 8¹ 1 8⁰ = 9 in base 10.
• 0100: This number converts to 1 8² 0 8¹ 0 * 8⁰ = 64 in base 10.
• 027: This number converts to 2 8¹ 7 8⁰ = 23 in base 10.

Python 3 (New Format)

In Python 3, the prefix '0o' must be used to indicate an octal constant. This helps differentiate octal numbers from decimal numbers more clearly.

• 0o11: This number converts to 1 8¹ 1 8⁰ = 9 in base 10.
• 0o100: This number converts to 1 8² 0 8¹ 0 * 8⁰ = 64 in base 10.
• 0o27: This number converts to 2 8¹ 7 8⁰ = 23 in base 10.

It's important to understand this behavior to avoid potential errors in your code. Always ensure that numeric values are entered correctly, and be aware of the different formats for representing octal numbers in Python.

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