How Does Python's Modulo Operator Handle Negative Numbers Differently Than C or C ?

Understanding the Modulo Operator's Behavior with Negative Numbers in Python

Unlike its counterparts in languages like C or C , Python's modulo operator (%) possesses a unique characteristic when it comes to negative numbers. It consistently returns a number that carries the same sign as the denominator, also known as the divisor.

Consider the expression "-5 % 4". Instead of resulting in "-1," as one might intuitively expect, Python evaluates it to "3." This outcome can be explained through the following mathematical operations:

• Floor division (-5) / 4 yields -1.25, and the floor function (floor()) converts it to the nearest integer, which is -2.
• (-5) % 4 can be computed as (-2 × 4 3) % 4, resulting in 3.

Python's choice of positive results over negative ones is driven by its practical usability. For instance, in the context of computing weekdays, the expression "(2 - N) % 7" conveniently calculates the day of the week that occurred N days before today. However, in C, negative results require manual adjustment to render them valid days.

In essence, Python's modulo operator ensures that the resulting number aligns with the divisor's sign, making it a valuable tool for various mathematical and practical applications.

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