The truth value of an array with more than one element is ambiguous. use a.any() or a.all().

For boolean arrays - and comparisons like <, <=, ==, !=, >= and > on NumPy arrays return boolean NumPy arrays - you can also use the element-wise bitwise functions (and operators): np.bitwise_and (& operator)

			
					import numpy as np
first = np.array([1, 2, 3])
second = bool(first)
print(second)

The output will be this error message:

			
					ValueError: The truth value of an array with more than one element is ambiguous. Use a.any() or a.all()

The element-wise equivalent for and would be the np.logical_and function, similarly you could use np.logical_or as equivalent for or.

Logical_and() function

			
					import numpy as np
arr = np.array([1, 2, 3])
print(np.logical_and(arr > 1, arr < 3))

			
					[False  True False]

Logical_or() function

			
					import numpy as np
arr1 = np.arange(5)
arr2 = np.arange(5, 10)
arr3 = np.array(['First', 'Second', 'Third', 'Fourth', 'Fifth'])
mask = np.logical_or(arr1 >= 3, arr2 < 3)
print(arr3[mask])

			
					['Fourth' 'Fifth']

			
					import numpy as np
np1 = np.zeros((3,))
np2 = np.ones((3,))
np1 in (np1, np2) # True

The Truth Value of an array with more than one element is ambiguous.

			
					np1 in (np2, np1)

ValueError   Traceback (most recent call last)
<gfd.py> in <module> 1 np1 in (np2, np1)

ValueError: The truth value of an array with more than one element is ambiguous. Use a.any() or a.all()

			
					np1 == np1

array([ True,  True,  True])

np1 is np1 or np1 == np1 # True

np1 is np2 or np1 == np2 # False

			
					any(np1 is e or np1 == e for e in (np2, np1)

ValueError    Traceback (most recent call last)
<gfd.py> in <module> 1 any(np1 is e or np1 == e for e in (np2, np1))

ValueError: The truth value of an array with more than one element is ambiguous. Use `a.any()` or `a.all()`.The issue does not occur when == is never broadcasted.

			
					np1 in (np3, np1) # True

Fix : The truth value of an array with more than one element is ambiguous. use a.any() or a.all()

Logical_and() function

Logical_or() function

The Truth Value of an array with more than one element is ambiguous.