Name

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  READ_IPAC_TABLE

Purpose

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  Read an IPAC ascii table from a file into an IDL structure

Explanation

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  Reads an IPAC ascii table from a file into an IDL structure. The
  definition of an IPAC-format table is currently here:
      http://irsa.ipac.caltech.edu/applications/DDGEN/Doc/ipac_tbl.html

Calling Sequence

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      info = read_ipac_table(filename, [change_null=change_null, /debug])

Inputs

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      FILENAME -- string giving the file with the input IPAC ascii table

Optional Input

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      CHANGE_NULL -- an integer value to be used when the IPAC table
                    has a non-numeric string for null values in an
                    integer column. The default is -9999. For
                    floating-point columns, this is 'NaN'.
      DEBUG -- enables some debugging statements

Outputs

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      info - Anonymous IDL structure containing information on the catalog. The structure
          tag names are taken from the column names. The structure will put header
          information in tags starting with "HEADER", e.g.
          HEADER_TABLE_HEADER, HEADER_DATA_UNITS, and HEADER_NULL_VALUES.
          Since the table column names may be altered if they are
          not valid IDL variable names, the original column names
          are saved as HEADER_COL_NAMES_ORIG. The original data
          type names are also saved as HEADER_COL_TYPES_ORIG.
          If the table is not valid, or contains no data, the function returns a value of -1

Procedures Used

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  GET_DATE, VALID_NUM

Modification History

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      Written by H. Teplitz, IPAC September 2010
      Allow long integer, convert blanks in numeric fields to null
      value - T. Brooke, IPAC May 2011
      Allow 64bit long; use valid_num to check - TB June 2013