# xarray.ufuncs.tan

`xarray.ufuncs.``tan` = <xarray.ufuncs._UFuncDispatcher object>

  xarray specific variant of numpy.tan. Handles xarray.Dataset, xarray.DataArray, xarray.Variable, numpy.ndarray and dask.array.Array objects with automatic dispatching.

  Documentation from numpy:

  tan(x, /, out=None, *, where=True, casting=’same_kind’, order=’K’, dtype=None, subok=True[, signature, extobj])

  Compute tangent element-wise.

  Equivalent to `np.sin(x)/np.cos(x)` element-wise.

  Parameters:

  x : array_like

  > Input array.

  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 freshly-allocated 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 keyword-only arguments, see the ufunc docs.

  Returns:

  y : ndarray

  > The corresponding tangent values.

  Notes

  If out is provided, the function writes the result into it, and returns a reference to out. (See Examples)

  References

  M. Abramowitz and I. A. Stegun, Handbook of Mathematical Functions. New York, NY: Dover, 1972.

  Examples

      >>> from math import pi
      >>> np.tan(np.array([-pi,pi/2,pi]))
      array([  1.22460635e-16,   1.63317787e+16,  -1.22460635e-16])
      >>>
      >>> # Example of providing the optional output parameter illustrating
      >>> # that what is returned is a reference to said parameter
      >>> out2 = np.cos([0.1], out1)
      >>> out2 is out1
      True
      >>>
      >>> # Example of ValueError due to provision of shape mis-matched `out`
      >>> np.cos(np.zeros((3,3)),np.zeros((2,2)))
      Traceback (most recent call last):
        File "<stdin>", line 1, in <module>
      ValueError: invalid return array shape