NumPy: Test element-wise of a given array for finiteness, positive or negative infinity, for NaN, for NaT, for negative infinity, for positive infinity
Write a NumPy program to test element-wise of a given array for finiteness (not infinity or not Not a Number), positive or negative infinity, for NaN, for NaT (not a time), for negative infinity, for positive infinity.
Sample Solution:
Python Code:
# Importing the NumPy library
import numpy as np
# Testing element-wise for finiteness (not infinity or not a Not a Number)
print("\nTest element-wise for finiteness (not infinity or not Not a Number):")
print(np.isfinite(1)) # Check if 1 is finite
print(np.isfinite(0)) # Check if 0 is finite
print(np.isfinite(np.nan)) # Check if NaN is finite
# Testing element-wise for positive or negative infinity
print("\nTest element-wise for positive or negative infinity:")
print(np.isinf(np.inf)) # Check if inf is infinite
print(np.isinf(np.nan)) # Check if NaN is infinite
print(np.isinf(np.NINF)) # Check if negative infinity is infinite
# Testing element-wise for NaN (Not a Number)
print("Test element-wise for NaN:")
print(np.isnan([np.log(-1.), 1., np.log(0)])) # Check if the elements are NaN
# Testing element-wise for NaT (not a time)
print("Test element-wise for NaT (not a time):")
print(np.isnat(np.array(["NaT", "2016-01-01"], dtype="datetime64[ns]"))) # Check for NaT
# Testing element-wise for negative infinity
print("Test element-wise for negative infinity:")
x = np.array([-np.inf, 0., np.inf])
y = np.array([2, 2, 2])
print(np.isneginf(x, y)) # Check for negative infinity
# Testing element-wise for positive infinity
print("Test element-wise for positive infinity:")
x = np.array([-np.inf, 0., np.inf])
y = np.array([2, 2, 2])
print(np.isposinf(x, y)) # Check for positive infinity
Sample Output:
Test element-wise for finiteness (not infinity or not Not a Number): True True False Test element-wise for positive or negative infinity: True False True Test element-wise for NaN: [ True False False] Test element-wise for NaT (not a time): [ True False] Test element-wise for negative infinity: [1 0 0] Test element-wise for positive infinity: [0 0 1]
Explanation:
In the above code –
print(np.isfinite(1)): This line checks if a given value is finite, returns True if it is, False otherwise. Here, the code checks if 1 is finite, which is True.
print(np.isfinite(0)): Similarly, this code checks if 0 is finite, which is True.
print(np.isfinite(np.nan)): Here, the code checks if np.nan (not-a-number) is finite, which is False.
print(np.isinf(np.inf)): Checks if a given value is positive or negative infinity. Here, the code checks if np.inf is infinite, which is True. print(np.isinf(np.nan)): Similarly, this code checks if np.nan is infinite, which is False.
print(np.isinf(np.NINF)): Checks if a given value is negative infinity. Here, the code checks if np.NINF is infinite, which is True.
print(np.isnan([np.log(-1.),1.,np.log(0)])): Checks if a given value is NaN (not-a-number). Here, the code checks if np.log(-1.),1.,np.log(0) are NaN, which is True for np.log(-1.) and np.log(0).
print(np.isnat(np.array(["NaT", "2016-01-01"], dtype="datetime64[ns]"))): Checks if a given value is a "not a time" (NaT) value. Here, the code checks if the array [ "NaT", "2016-01-01"] is a NaT value, which is True for the first element.
x = np.array([-np.inf, 0., np.inf]) y = np.array([2, 2, 2]) print(np.isneginf(x, y)): Checks if a given value is negative infinity with support for broadcasting. Here, the code checks if -np.inf is a negative infinity with respect to each element of y, which returns an array [ True, False, False ].
x = np.array([-np.inf, 0., np.inf]) y = np.array([2, 2, 2]): This line defines two arrays x and y for the next line of code.
Python-Numpy Code Editor: