isinf() to check number is positive or negative infinity or not in Python

isinf(number) returns Boolean , True if the input number is positive infinite or negative infinity, False otherwise.

isinf(n)

Example

import math
print(math.isinf(2))     # False
print(math.isinf(-2))    # False
print(math.isinf(0.0))   # False
print(math.isinf(0/1))   # False
print(math.isinf(0.0/1)) # False

Note : 0.0 is considered finite.

import math
print(math.isinf(float('inf')))   # True
print(math.isinf(float('-inf')))  # True
print(math.isinf(float('nan')))   # False

Infinity in Calculations:
Overflowing a large number results in infinity.

print(math.isinf(1e308 * 2))  # Output: True

Infinity from Division:
Division by zero results in positive infinity.

print(math.isinf(1 / 0.0))  # Output: True

Using with Lists:
This filters out infinity values from a list.

numbers = [10, float('inf'), float('-inf'), 42]
inf_values = [n for n in numbers if math.isinf(n)]
print(inf_values)  # Output: [inf, -inf]

Difference Between isinf() and isnan()

import math
print(math.isinf(float('inf')))  # True
print(math.isnan(float('nan')))  # True

Use Case: Handling Division by Zero

import math

try:
    result = 1.0 / 0.0
except ZeroDivisionError:
    result = float('inf')

if math.isinf(result):
    print("Result is infinity")

isfinite()

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Subhendu Mohapatra

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