Copysign() Function - Python Math Module

Overview:

  • The function copysign() from the math module, when passed a magnitude(m) and a number(ss) as a sign source, the function copies the sign from ss to m
  • Python does not have a sign() function. Simulating sign() function using copysign() is possible in two ways:
    • Give a negative number as ss and 1 as m to copysign(), which will return -1.
    • Give a positive number as ss and 1 as m to copysign(), which will return 1. 

Example 1:

# Example program that copies a sign from another number
# for a given number and returns a float
import math

# Copy the sign of a positive number to a negative number
v = math.copysign(-4, 3)
print(v)

# Copy the sign of a negative number to a positive number
v = math.copysign(4, -3)
print(v)

# Copy the sign of a negative number to a negative number
v = math.copysign(-4.1, -4)
print(v)
print(type(v))

Output:

4.0

-4.0

-4.1

<class 'float'>

Example 2:

# Example Python program simulating sign function
import math

# Sign(negative quantity)
magnitude   = 1
signSource  = -4
value = math.copysign(magnitude, signSource)
print(value)

# Sign(postive quantity)
magnitude   = 1
signSource  = 4
value = math.copysign(magnitude, signSource)
print(value)

Output:

-1.0

1.0

 


Copyright 2022 © pythontic.com