#### 8.2.6.12 categorical.mergecats ¶

Method: `out =` mergecats `(obj, oldcats)` ¶
Method: `out =` mergecats `(obj, oldcats, newcat)` ¶

  Merge multiple categories.

  Merges the categories oldcats into a single category. If newcat is specified, that new category is added if necessary, and all of oldcats are merged into it. newcat must be an existing category in obj if obj is ordinal.

  If newcat is not provided, all of odcats are merged into `oldcats{1}`.