Python | ldexp() function

ldexp() function is one of the Standard math library function in Python, which returns x * (2**i). This is also called as inverse of Python frexp() function.

Syntax: math.ldexp(x, i) 

Parameters: x : Any valid number (+ve or -ve) i : Any valid number (+ve or -ve) 

Returns : Returns the value of x * (2**i).

Time Complexity: O(1)

Auxiliary Space: O(1)

For example, if x = 3 and i = 4 then, Math.ldexp(3, 4) = 3*16 = 48. 

Code #1:

Python3

# Python3 code demonstrate ldexp() function

# importing math library
import math

# ldexp() Function on +ve nd -ve Numbers
print(math.ldexp(9, 3))
print(math.ldexp(-5, 2))

# ldexp() Function on fractional Number
print(math.ldexp(3.5, 2))
print('%.2f' %math.ldexp(-6.8, 3))

Output:

72.0
-20.0
14.0
-54.40

Code #2:

Python3

# Python3 code demonstrate ldexp() function

# importing math library
import math

# Tuple Declaration
tpl = (9, -5, 3.5, -6.8)

# List Declaration
lst = [13, 4, 8.4, -6.7]

# ldexp() Function on +ve nd -ve Numbers
print(math.ldexp(tpl[0], 3))
print(math.ldexp(tpl[3], 2))

# ldexp() Function on fractional Number
print(math.ldexp(lst[1], 2))
print('%.2f' %math.ldexp(lst[2], 3))

Output:

72.0
-27.2
16.0
67.20

Code #3: If the X value or i value argument is not a number, ldexp() function will return TypeError. 

Python3

# Python3 code demonstrates when error occurs

# importing the math library
import math

# string value taken
print(math.ldexp('25', 5))
print(math.ldexp(25, '5'))

Output:

TypeError: a float is required
TypeError: a float is required