WHERE_TAG

       Like WHERE but works on structure tag names

       Obtain subscripts of elements in structure array for which
       a particular Tag has values in a range or matching specified values.
       Like the WHERE function but for use with structures

                       Structures

        w = where_tag( struct, [ Nfound,  TAG_NAME=, TAG_NUMBER = , RANGE =,
                               VALUES =, RANGE =, ISELECT =, /NOPRINT ]

       Struct = structure array to search.

       User *must* specify (1) TAG_NAME or TAG_NUMBER to search, and (2)
               the VALUES or RANGE to search on
       TAG_NAME = Scalar string specifying Tag Name
       TAG_NUMBER = otherwise give the Tag Number,
       RANGE = [min,max] range to search for in Struct,
       VALUES = one or array of numbers to match for in Struct,
       ISELECT= specifies indices to select only part of structure array,
               (use it to recycle subscripts from previous searches).
       /NOPRINT = suppress informational messages about nothing found.

       Nfound = # of occurences found.

       Function returns subscripts (indices) to desired elements.

       Suppose STR is a structure with tags CAT_NO:indgen(10), and
               NAME:strarr(10).   Find the indices where STR.CAT_NO is
               between 3 and 5.
       IDL> print, WHERE_TAG( str, TAG_NAME = 'CAT_NO', VALUE = [3,4,5] )  ;or
       IDL> print, WHERE_TAG( str, TAG_NUM = 0, RANGE = [3,5])

       Get tag number and apply the WHERE function appropriately.

       written 1990 Frank Varosi STX @ NASA/GSFC
       Stop printing "Tag  not found" with /NOPRINT, CD Pike 8-Jun-93

[Home Page] [Software, Documentation] [IDL Documentation] [Quick Reference] [Feedback]