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# numpy.sign

`numpy.``sign`(x[, out]) = <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.
  Returns: | y : ndarray The sign of x.

  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(5-2j)
      (1+0j)