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
This condition is broadcast over the input. At locations where the condition is True, the out array will be set to the ufunc result. Elsewhere, the out array will retain its original value. Note that if an uninitialized out array is created via the default
out=None
, locations within it where the condition is False will remain uninitialized. **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)