numpy.sign¶

numpy.
sign
(x, /, out=None, *, where=True, casting='same_kind', order='K', dtype=None, subok=True[, signature, extobj]) = <ufunc 'sign'>¶ Returns an elementwise indication of the sign of a number.
The
sign
function returns1 if x < 0, 0 if x==0, 1 if x > 0
. nan is returned for nan inputs.For complex inputs, the
sign
function returnssign(x.real) + 0j if x.real != 0 else sign(x.imag) + 0j
.complex(nan, 0) is returned for complex nan inputs.
Parameters:  x : array_like
Input values.
 out : ndarray, None, or tuple of ndarray and None, optional
A location into which the result is stored. If provided, it must have a shape that the inputs broadcast to. If not provided or None, a freshlyallocated array is returned. A tuple (possible only as a keyword argument) must have length equal to the number of outputs.
 where : array_like, optional
Values of True indicate to calculate the ufunc at that position, values of False indicate to leave the value in the output alone.
 **kwargs
For other keywordonly arguments, see the ufunc docs.
Returns:  y : ndarray
The sign of x. This is a scalar if x is a scalar.
Notes
There is more than one definition of sign in common use for complex numbers. The definition used here is equivalent to which is different from a common alternative, .
Examples
>>> np.sign([5., 4.5]) array([1., 1.]) >>> np.sign(0) 0 >>> np.sign(52j) (1+0j)