numpy.sign(x, /, out=None, *, where=True, casting='same_kind', order='K', dtype=None, subok=True[, signature, extobj]) = <ufunc 'sign'>
Returns an element-wise indication of the sign of a number.
The sign
function returns -1 if x < 0, 0 if x==0, 1 if x > 0
. nan is returned for nan inputs.
For complex inputs, the sign
function returns sign(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 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 keyword-only arguments, see the ufunc docs. |
---|---|
Returns: |
y : ndarray The sign of |
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, .
>>> np.sign([-5., 4.5]) array([-1., 1.]) >>> np.sign(0) 0 >>> np.sign(5-2j) (1+0j)
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https://docs.scipy.org/doc/numpy-1.14.2/reference/generated/numpy.sign.html