fmod() to get Modulus of given input numbers in Python

Module of input numbers

fmod(x,y)

Return value is modulus of two input numbers with sign of x. Data type of return value is float.

Example

print(math.fmod(10,2)) # 0.0
print(math.fmod(10,3)) # 1.0
print(math.fmod(10,4)) # 2.0

Output will carry sign of x

print(math.fmod(10,-2))   # 0.0
print(math.fmod(10,-3))   # 1.0
print(math.fmod(10,4))    # 2.0
print(math.fmod(-10,4))   # -2.0

x is float here

print(math.fmod(10.34,4)) # 2.34
print(math.fmod(10,0))    # ValueError: math domain error

Using for loop

for i in range(0,10):
    print("fmod(",i,",2) = ",math.fmod(i,2))

Output

fmod( 0 ,2) =  0.0
fmod( 1 ,2) =  1.0
fmod( 2 ,2) =  0.0
fmod( 3 ,2) =  1.0
fmod( 4 ,2) =  0.0
fmod( 5 ,2) =  1.0
fmod( 6 ,2) =  0.0
fmod( 7 ,2) =  1.0
fmod( 8 ,2) =  0.0
fmod( 9 ,2) =  1.0

fmod() is generally preferred when working with floats ( data type ) , while Python’s x % y is preferred when working with integers.
Python modulo operator always return the remainder having the same sign as the divisor.
Watch the output and think why they are different?
Example 1

import math
x=-25
y=3
print(math.fmod(x,y))  # output -1.0
print(x % y)           # output 2

Example 2

import math
x=25
y=-3
print(math.fmod(x,y)) # output 1.0
print(x % y)          # output -2

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Subhendu Mohapatra

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