divmod() in Python and its application

The divmod() method in python takes two numbers and returns a pair of numbers consisting of their quotient and remainder.
Syntax :

divmod(x, y)
x and y : x is numerator and y is denominator
x and y must be non complex

Examples:

Input : x = 9, y = 3
Output :(3, 0)

Input : x = 8, y = 3
Output :(2, 2)

Explanation : The divmod() method takes two parameters x and y, where x is treated as numerator and y is treated as denominator. The method calculates both x / y and x % y and returns both the values.

If x and y are integers, the return value is
```
(x / y, x % y)
```
.

If x or y is a float, the result is

(q, x % y), where q is the whole part of the quotient.

# Python3 code to illustrate divmod() 
# divmod() with int 
print('(5, 4) = ', divmod(5, 4)) 
print('(10, 16) = ', divmod(10, 16)) 
print('(11, 11) = ', divmod(11, 11)) 
print('(15, 13) = ', divmod(15, 13)) 
  
# divmod() with int and Floats 
print('(6.0, 5) = ', divmod(8.0, 3)) 
print('(3, 9.0) = ', divmod(3, 8.0)) 
print('(13.5, 6.2) = ', divmod(7.5, 2.5)) 
print('(1.6, 10.7) = ', divmod(2.6, 0.5)) 

Output:

(5, 4) =  (1, 1)
(10, 16) =  (0, 10)
(11, 11) =  (1, 0)
(15, 13) =  (1, 2)
(6.0, 5) =  (2.0, 2.0)
(3, 9.0) =  (0.0, 3.0)
(13.5, 6.2) =  (3.0, 0.0)
(1.6, 10.7) =  (5.0, 0.10000000000000009)

Errors And Exceptions

If either of the arguments, say x and y, is a float, the result is (q, x%y). Here, q is the whole part of the quotient.
If the second argument is 0, it returns Zero Division Error
If the first argument is 0, it returns (0, 0)

Practical Application : Check if a number is prime or not using divmod() function.
Examples:

Input : n = 7
Output :Prime

Input : n = 15
Output :Not Prime

Algorithm

Initialise a new variable, say x with the given integer and a variable counter to 0
Run a loop till the given integer becomes 0 and keep decrementing it.
Save the value returned by divmod(n, x) in two variables, say p and q
Check if q is 0, this will imply that n is perfectly divisible by x, and hence increment the counter value
Check if the counter value is greater than 2, if yes, the number is not prime, else it is prime

# Python code to find if a number is 
# prime or not using divmod() 
  
# Given integer 
n = 15
x = n 
  
# Initialising counter to 0 
count = 0
while x != 0: 
    p, q = divmod(n, x) 
    x-= 1
    if q == 0: 
        count+= 1
if count>2: 
    print('Not Prime') 
else: 
    print('Prime') 

Output:

Not Prime

More Applications:

# Sum of digits of a number using divmod 
num = 86
sums = 0
while num!=0: 
    use = divmod(num, 10) 
    dig = use[1] 
    sums = sums + dig 
    num = use[0] 
print(sums) 

Output:

# reversing a number using divmod 
num = 132
pal = 0
while num!=0: 
    use = divmod(num, 10) 
    dig = use[1] 
    pal = pal*10+dig 
    num = use[0] 
print(pal) 

Output:

Co-Author : Chinmoy Lenka

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