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DBMATCH

DBMATCH

Name


      DBMATCH

Purpose


      Find the entry number in a database for each element of item values

Explanation


      DBMATCH() is especially useful for finding a one-to-one
      correspondence between entries in different databases, and thus to
      create the vector needed for database pointers.

Calling Sequence


      list = DBMATCH( item, values, [ listin, /FULLSTRING ] )

Inputs


      ITEM - Item name or number, scalar
      VALUES - scalar or vector containing item values to search for.

Optional Inputs


      LISTIN - list of entries to be searched. If not supplied, or
              set to -1, then all entries are searched

Output


      LIST - vector of entry numbers with the same number of elements as
              VALUES. Contains a value of 0 wherever the corresponding item
              value was not found.

Optional Input


      /FULLSTRING - By default, one has a match if a search string is
              included in any part of a database value (substring match).
              But if /FULLSTRING is set, then all characters in the database
              value must match the search string (excluding leading and
              trailing blanks). Both types of string searches are case
              insensitive.

Notes


      DBMATCH is meant to be used for items which do not have duplicate values
      in a database (e.g. catalog numbers). If more than one entry is found
      for a particular item value, then only the first one is stored in LIST.
      When linked databases are opened together, DBMATCH can only be
      used to search on items in the primary database.

Example


      Make a vector which points from entries in the Yale Bright Star catalog
      to those in the Hipparcos catalog, using the HD number
      IDL> dbopen, 'yale_bs' ;Open the Yale Bright star catalog
      IDL> dbext, -1, 'HD', hd ;Get the HD numbers
      IDL> dbopen, 'hipparcos' ;Open the Hipparcos catalog
      IDL> list = dbmatch( 'HD', HD) ;Get entries in Hipparcos catalog
                                        ;corresponding to each HD number.

Procedure Calls


      DB_ITEM, DB_ITEM_INFO(), DBEXT, DBFIND_SORT()

Revision History


      Written, W. Landsman STX February, 1990
      Fixed error when list in parameter used May, 1992
      Faster algorithm with sorted item when listin parameter supplied
      Added keyword FULLSTRING,check for empty database, William Thompson,
              GSFC, 15 March 1995
      Work for more than 32767 values, added CATCH W. Landsman July 1997
      Change some loop variables to type LONG, W. Landsman July 1999
      Remove loop for substring searches (faster) W. landsman August 1999
      Replace DATATYPE() with size(/TNAME) W. Landsman November 2001
      Fixed typo when search on sorted items W. Landsman February 2002
      Fixed bug from Nov 2001 where /FULLSTRING was always set. W.L Feb 2007



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