isfinite() to check number is finite or not in Python

isfinite(number) returns Boolean , True if the input number is finite, returns False otherwise.

isfinite(n)

Example

import math
print(math.isfinite(2))     # True
print(math.isfinite(-2))    # True
print(math.isfinite(0.0))   # True 
print(math.isfinite(0/1))   # True 
print(math.isfinite(0.0/1)) # True

Note : 0.0 is considered finite.

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

Large Number:
Even large numbers are considered finite.

print(math.isfinite(1e308))  # Output: True

Using Lists:

values = [3.5, float('inf'), -10, float('nan')]
finite_vals = [v for v in values if math.isfinite(v)]
print(finite_vals)  # Output: [3.5, -10]

These examples show how math.isfinite() distinguishes between finite numbers and special values like NaN or infinity.
isinf()

Example 1: Handling Division by Zero

import math
try:
    result = 1 / 0
except ZeroDivisionError:
    result = float('inf')
print(math.isfinite(result))  # Output: False

Output:

False

Example 4: Handling Infinite Loops with math.isfinite()

import math
def process_data(value):
    if not math.isfinite(value):
        return "Invalid input: infinite"
    return value * 2

print(process_data(float('inf')))  # Output: Invalid input: infinite

Output:

Invalid input: infinite

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Subhendu Mohapatra

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