Introduction Python Frexp() Method with Examples

The Python frexp function is one of the Python Mathematical Functions used to return the mantissa and exponent of x, as pair (m, e). Where m is a float value, and e is an integer value. In this section, we discuss how to use frexp function in Python Programming language with example.

Python Frexp()

frexp() function is one of the Standard math Library function in Python.

It returns mantissa and exponent as a pair (m, e) of a given value x, where mantissa m is a floating point number and e exponent is an integer value. m is a float and e is an integer such that x == m * 2**e exactly.

If x is zero, returns (0.0, 0), otherwise 0.5 <= abs(m) < 1. This is used to “pick apart” the internal representation of a float in a portable way.

Syntax of math.frexp() method:

    math.frexp(n)

Here n is a number for which we will find mantissa and exponent.

Parameters:

Any valid number (positive or negative).

Return Value

Returns mantissa and exponent as a pair (m, e) value of a given number x.

Examples of Python Frexp() method

Example 1

# app.py

# Importing math library
import math

# Demonstrating working of frexp()
# Using different types of value of x

# When x is positive number
x = 5
print("Pair of mantissa and exponent of ", x, " is: ", math.frexp(x))

# When x is float type number
x = 6.4
print("Pair of mantissa and exponent of ", x, " is: ", math.frexp(x))

# When x is a negative number
x = -32
print("Pair of mantissa and exponent of ", x, " is: ", math.frexp(x))

# Declaring a list
x = [4, 3, 7]

# Using frexp() with the 3rd value of the list
print("Pair of mantissa and exponent of ", x[2], " is: ", math.frexp(x[2]))

# When x is not a number
x = '41'
print("Pair of mantissa and exponent of ", x, " is: ", math.frexp(x))

Output

Pair of mantissa and exponent of  5  is:  (0.625, 3)
Pair of mantissa and exponent of  6.4  is:  (0.8, 3)
Pair of mantissa and exponent of  -32  is:  (-0.5, 6)
Pair of mantissa and exponent of  7  is:  (0.875, 3)
Traceback (most recent call last):
  File "frexp.py", line 27, in <module>
    print("Pair of mantissa and exponent of ",x," is: ",math.frexp(x))
TypeError: must be real number, not str

In the above code, we have taken different types of values of x and checked the output using the frexp() method. We can see that in each case, an output is in (m,e) pair.

At last, when we have declared value of x as a character, a TypeError is returned.

Example 2

Use frexp() with Python tuple and list

See the following code in which we have defined Python list and tuple.

# app.py

import math

# creating a list
lst = [11, 21.11, 21.19, 30]

# creating a tuple
tpl = (-15.31, -41.31, -11.21, 46.19)

# calculating mantissa and exponent
# of 1st, 3rd elements in list
print(math.frexp(lst[0]))
print(math.frexp(lst[2]))

# calculating mantissa and exponent
# of 2nd, 3rd and 4th elements in tuple
print(math.frexp(tpl[1]))
print(math.frexp(tpl[2]))
print(math.frexp(tpl[3]))

Output

python3 app.py
(0.6875, 4)
(0.6621875, 5)
(-0.64546875, 6)
(-0.700625, 4)
(0.72171875, 6)

Python frexp() method is one of the Python Mathematical Functions that is used to return the mantissa and exponent of x, as a pair (m, e) where m is the float value and e is an integer value.

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