Python math function | modf()

Last Updated : 14 Feb, 2023

modf() function is an inbuilt function in Python that returns the fractional and integer parts of the number in a two-item tuple. Both parts have the same sign as the number. The integer part is returned as a float. Syntax :

modf(number)

Time Complexity: O(1)

Auxiliary Space: O(1)

Parameter :

There is only one mandatory parameter which is the number.

Returns : This method returns the fractional and integer parts of number in a two-item tuple. Both parts have the same sign as the number. The integer part is returned as a float. Exception :

TypeError:  If anything other than a float number is passed, it returns a type error.

Below is the Python3 implementation of modf() method : Code #1

Python3

# Python3 program to demonstrate the function modf()
 
# This will import math module
import math   
 
# modf() function used with a positive number
print("math.modf(100.12) : ", math.modf(100.12))
 
# modf() function used with a negative number
print("math.modf(-100.72) : ", math.modf(-100.72)) 
 
print("math.modf(2) : ", math.modf(2)) 

Output :

math.modf(100.12) :  (0.12000000000000455, 100.0)
math.modf(-100.72) :  (-0.7199999999999989, -100.0)
math.modf(2) :  (0.0, 2.0)

Code #2 : TypeError

Python3

# Python3 program to demonstrate the  
# error in function modf()
 
# This will import math module
import math   
 
# modf() function used with a positive number
print("math.modf(100.12) : ", math.modf("100.12"))

Output :

Traceback (most recent call last):
  File "/home/fa6d7643de17bafe9a0e0693458e4bdb.py", line 9, in 
    print("math.modf(100.12) : ", math.modf("100.12"))
TypeError: a float is required

Code #3 :

Python3

# Python3 program to demonstrate the 
# error in function modf()
 
# This will import math module
from math import modf
 
lst = [3.12, -5.14, 13.25, -5.21]
tpl = (33.12, -15.25, 3.15, -31.2)
 
 
# modf() function on elements of list
print("modf() on First list element : ", modf(lst[0]))
print("modf() on third list element : ", modf(lst[2]))
 
# modf() function on elements of tuple
print("modf() on Second tuple element : ", modf(tpl[1]))
print("modf() on Fourth tuple element : ", modf(tpl[3]))

Output :

modf() on First list element :  (0.1200000000000001, 3.0)
modf() on third list element :  (0.25, 13.0)
modf() on Second tuple element :  (-0.25, -15.0)
modf() on Fourth tuple element :  (-0.1999999999999993, -31.0)

Practical Application : Given two float numbers, multiply the fractional part and return the answer. Code #4 :

Python3

# Python3 program to demonstrate the 
# application of function modf()
 
# This will import math module
import math   
 
# modf() function to multiply fractional part 
a = math.modf(11.2) 
b = math.modf(12.3)
 
# Multiply the fractional part as is stored  
# in 0th index of both the tuple
print(a[0]*b[0])