# Test element-wise for positive or negative infinity in Numpy

To test element-wise for positive or negative infinity, use the numpy.isinf() method in Python Numpy. Returns a boolean array of the same shape as x, True where x == +/-inf, otherwise False.

NumPy uses the IEEE Standard for Binary Floating-Point for Arithmetic (IEEE 754). Errors result if the second argument is supplied when the first argument is a scalar, or if the first and second arguments have different shapes.

## Steps

At first, import the required library −

import numpy as np

To test element-wise for positive or negative infinity, use the numpy.isinf() method in Python Numpy.

Checking for numbers −

print("Infinite? ", np.isinf(1))
print("Infinite? ", np.isinf(0))

Checking for float −

print("Infinite? ", np.isinf(14.))
print("Infinite? ", np.isinf(3.6))

Checking for NaN −

print("Infinite? ", np.isinf(np.nan))
print("Infinite? ", np.isinf(np.NAN))

Checking for infinity −

print("Infinite? ", np.isinf(np.inf))
print("Infinite? ", np.isinf(np.NINF))

Checking for log −

print("Infinite? ", np.isinf(np.log(1)))
print("Infinite? ", np.isinf(np.log(2)))

## Example

import numpy as np

# To test element-wise for positive or negative infinity, use the numpy.isinf() method in Python Numpy

# Checking for numbers
print("Infinite? ", np.isinf(1))
print("Infinite? ", np.isinf(0))

# Checking for float
print("Infinite? ", np.isinf(14.))
print("Infinite? ", np.isinf(3.6))

# Checking for NaN
print("Infinite? ", np.isinf(np.nan))
print("Infinite? ", np.isinf(np.NAN))

# Checking for infinity
print("Infinite? ", np.isinf(np.inf))
print("Infinite? ", np.isinf(np.NINF))

# Checking for log
print("Infinite? ", np.isinf(np.log(1)))
print("Infinite? ", np.isinf(np.log(2)))

## Output

Infinite? False

Infinite? False

Infinite? False

Infinite? False

Infinite? False

Infinite? False

Infinite? True

Infinite? True

Infinite? False

Infinite? False