.. highlightlang:: us

.. index:: ST_complement

.. _st_complement:

ST_complement
=============

.. us.tag  ST_complement NOTREADYENGLISH STR New300 Changed412

Compute the complement of *a* in *b* (the elements of *b* that are not in *a*).

.. function::  c = ST_complement(a, b)
               c = ST_complement(a, b, rsNull)

.. us.return

**Return Value**

*c* is a vector with the elements of *b* that are not in *a* or 0 (for real) or
"" (for string).

.. us.params

**Parameters**

.. uparam:: a

   *a* is a string or real matrix.

.. uparam:: b

   *b* is a string or real matrix.

.. uparam:: rsNull

   *rsNull* is the return value if *b* contains only elements that are in *a*.
   The parameter is only used with real matrices.

.. us.example

**Example**

::

   * ST_complement([2,3,5,7], [2,4,9])
   *    4.000    9.000
   *
   * ST_complement(["one", "two", "three"], ["two", "four", "five"])'
   four
   five
   *
   * ST_complement([2,5], [1,2,3,4,5,6])
       1.0000     3.0000     4.0000     6.0000 

.. seealso::
   :ref:`overview-strings`,
   :ref:`ST_intersection`,
   :ref:`ST_set`,
   :ref:`ST_union`

:sub:`id-975428`