CCfits - HEASARC - NASA

10 Selecting Table Data 24
const string inFileName("atestfil.fit");
const string outFileName("btestfil.fit");
int status(0);
status = 0;
remove(outFileName.c_str());
// Delete old file if it already exists
// open the existing FITS file
FITS inFile(inFileName);
// custom constructor FITS::FITS(const string&, const FITS&) for
// this particular task.
FITS outFile(outFileName,inFile);
// copy extension by number...
outFile.copy(inFile.extension(2));
// copy extension by name...
outFile.copy(inFile.extension("TABLE_BINARY"));
return 0;
}
10 Selecting Table Data
This function demonstrates the operation of filtering a table by selecting rows that
satisfy a condition and writing them to a new file, or overwriting a table with the filtered
data. A third mode, where a filtered dataset is appended to the file containing the source
data, will be available shortly, but is currently not supported by cfitsio.
The expression syntax for the conditions that may be applied to table data are described
in the cfitsio manual. In the example below, we illustrate filtering with
a boolean expression involving one of the columns.
The two flags at the end of the call to FITS::filter are an ‘overwrite’ flag - which only
has meaning if the inFile and outFile are the same, and a ’read’ flag. overwrite defaults
to true. The second flag is a ’read’ flag which defaults to false. When set true the user
has immediate access to the filtered data.
(Also see the section "Reading with Extended File Name Syntax")
int selectRows()
{
const string inFile("atestfil.fit");
const string outFile("btestfil.fit");
const string newFile("ctestfil.fit");
remove(newFile.c_str());
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