`numpy:isreal`

Signature

def isreal(x)

Returns a bool array, where True if input element is real.

If element has complex type with zero imaginary part, the return value for that element is True.

isreal may behave unexpectedly for string or object arrays (see examples)

import numpy as np
a = np.array([1+1j, 1+0j, 4.5, 3, 2, 2j], dtype=complex)
np.isreal(a)

✓

array([False,  True,  True,  True,  True, False])

The function does not work on string arrays.

a = np.array([2j, "a"], dtype="U")

✓

np.isreal(a)  # Warns about non-elementwise comparison

✗

array([False, False])

Returns True for all elements in input array of ``dtype=object`` even if any of the elements is complex.

a = np.array([1, "2", 3+4j], dtype=object)
np.isreal(a)

✓

array([ True,  True,  True])

isreal should not be used with object arrays

a = np.array([1+2j, 2+1j], dtype=object)
np.isreal(a)

✓

array([ True,  True])