# coyote: CGSETINTERSECTION

- coyote/Utilities
- [Source code]

Description

      This function is used to find the intersection between two sets of integers.

Categories

      Utilities

Returns

      A vector of values that are found in both set_a and set_b.

Params

      set_a: in, required, type=integer
         A vector of integers.
      set_b: in, required, type=integer
         A vector of integers.

Keywords

      count: out, optional, type=integer
           This keyword contains the number of elements in the intersection vector.
      indices_a: out, optional, type=integer
           The indices in vector A where the intersected values appear. Note, this requires
           the intersected points be unique in each vector. The `Positions` keyword will
           return ALL the positions of the match, even if there are non-unique matches.
      indices_b: out, optional, type=integer
           The indices in vector B where the intersected values appear. This assumes that
           the intersected points are represented uniquely in the A and B vectors.
      noresult: in, optional
           Set this keyword to a value that will be returned from the function
           if no intersection between the two sets of numbers is found. By default, -1.
      positions: out, optional, type=integer
           This keyword returns the positions or locations in A where the values
           in B appear.
      success: out, optional, type=boolean
           This keyword is set to 1 if an intersection was found, and to 0 otherwise.

Examples

      Here is how to use this program::
        IDL> set_a = [1,2,3,4,5]
        IDL> set_b = [4,5,6,7,8,9,10,11]
        IDL> Print, cgSetIntersection(set_a, set_b)
             4   5
      e http://www.idlcoyote.com/tips/set_operations.html for other types of set operations.

Author

      FANNING SOFTWARE CONSULTING::
         David W. Fanning
         1645 Sheely Drive
         Fort Collins, CO 80526 USA
         Phone: 970-221-0438
         E-mail: david@idlcoyote.com
         Coyote's Guide to IDL Programming: http://www.idlcoyote.com

History

      Change History::
         Written by: David W. Fanning, October 31, 2009, from code originally supplied to the IDL
            newsgroup by Research Systems software engineers.
         Yikes, bug in original code only allowed positive integers. Fixed now. 2 Nov 2009. DWF.
         Fixed a problem when one or both of the sets was a scalar value. 18 Nov 2009. DWF.
         Added a POSITIONS keyword. 30 Nov 2012. DWF.
         Added a COUNT keyword 3 Dec 2012. DWF.
         Added INDICES_A and INDICES_B keywords at R.G. Stockwell's suggestion. 13 Dec 2012. DWF.

Copyright

      Copyright (c) 2009-2013, Fanning Software Consulting, Inc.