Using the Python Modulo % Operator

Python supports a wide range of arithmetic operators that you can use when working with numbers in your code. One of these operators is the modulo operator (%), which returns the remainder of dividing two numbers. Modular operations are useful to check if a number is even or odd, simplifying cycling through data, and doing non-decimal based units conversion.

Python’s % operator’s been around for a long time. The code shown you has all been tested using Python 3.9, but you should be able to use it in pretty much any version of Python.

[sourabhch]

That is a brief explanation, no one has ever taught me about the modular arithmetic like this. Thanks for your effort really great and helpful videos. Please provide us a playlist for learning python from the scratch.

[pujipangesty]

Thanks so much. After following the explanation, I think a % b = a - b * (a // b) which yields a remainder, congruent is the same remainder.

Congruence:
12.5% -5.5 = -4.0
-15 % -11 = -4

12.5 - (-5.5) * (12.5 // -5.5) == -15 - (-11) * (-15 // -11) -> True

[Zoheb]

Thank you! You are a true human being for helping other humans! You shall be rewarded.

[lawrencedoliveiro]

Note that Python’s modulo operator is defined in a sensible way. That means the result has the same sign as the divisor:

>>> (-5) % 3
1
>>> (-4) % 3
2

In some other languages, you would get the answers -2 and -1 instead.

Trivia question: if your language’s modulo operator is broken, how would you wrap it in a simple expression to get the Python-style answer?

[AtlantaTerry]

Thank you for putting this tutorial together.
One thing, the text is VERY soft which makes it difficult to read.

[sambitsuranjan]

WHich modulo result is correct mathematically? Using '%' or using fmod ?

[ebadhaider]

how to calculate modulus inverse without using function in python?

[DeusKnight]

1:14 Saving this for later because I know I'll forget

[GarethHUE]

r=13-(12*floor(13/12))... What's floor?

Besides lava...