2.8. Modulus operator¶
The modulus operator works on integers and yields the
remainder when the first operand is divided by the second. In Python,
the modulus operator is a percent sign ( % ). The syntax is the same as
for other operators:
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So 7 divided by 3 is 2 with 1 left over.
The modulus operator turns out to be surprisingly useful. For example,
you can check whether one number is divisible by another: if x %
y is zero, then x is divisible by y.
You can also extract the right-most digit or digits from a number. For
example, x % 10 yields the right-most digit of
x (in base 10). Similarly, x % 100 yields the
last two digits.
- 0
- This would be correct if it was
18 % 2, but what is the remainder of 18 divided by 5? - 1
- This would be correct if it was
18 % 17, since 17 goes into 18 one time and the remainder is 18 - 17 = 1. - 2
- What is the highest multiple of 5 that is less than or equal to 18? The remainder is 18 - that number.
- 3
- The reminder is 3 since 5 goes into 18 three times (15) and 18 - 15 = 3.
csp-10-2-2: What is the result of 18 % 5?
- 2
- The remainder when a smaller number is divided by a larger number is the smaller number.
- 8
- This would be true if it was 2 raised to the 3rd power, but it is modulus.
- 1
- This would be true if it was
3 % 2. - 0.66666
- This would be true if it was floating point division, but it is modulus.
csp-10-2-3: What is the result of 2 % 3?
-
csp-10-2-4: Match each expression with the type of division the operator performs.
Try out these expressions in terminal or review the operators and operands section.
- 7 / 2
- division
- 90 // 4
- floored division
- 45 % 6
- remainder