[gnuastro-devel] [task #13579] Utility for table displaying and manipulation

[Mohammad Akhlaghi]

Update of task #13579 (project gnuastro):

                  Status:             In Progress => Done                   
        Percent Complete:                     10% => 100%                   
             Open/Closed:                    Open => Closed                 

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Follow-up Comment #2:

An initial version of the new `Table' utility was made and is now pushed into
the main repo. Some simple tests have also been written for it and a section
was added to the book, explaining everything with examples.

Operating on binary FITS tables is now as easy as plain text files, just
replace `cat' with `asttable'. These examples are taken from the top of the
"Invoking Table" section:


## Get the table column information (name, data type, or units)
$ asttable bintab.fits --information

## Only print those columns which have a name starting with "MAG_"
$ asttable bintab.fits --columns=^MAG_

## Only print the 2nd column, and the third column multiplied by 5
$ asttable bintab.fits | awk '@{print $2, address@hidden'

## Only print those rows with a value in the 10th column above 100000
$ asttable bintab.fits | awk '$10>10e5 @address@hidden'

## Sort the output columns by the third column, save output
$ asttable bintab.fits | sort -k3 > output.txt

## Convert a plain text table to a binary FITS table
$ asttable plaintext.txt --output=inbinary.fits


Before starting to work on adding this new utility, I also made a general
TEMPLATE utility. So it will be really easy to add future new utilities (just
copy this directory and rename TEMPLATE everywhere in that directory).

Ofcourse table can still use a lot of work to become even better and more
robust. But I couldn't put much more time now. I have made a lot of comments
in the commit messages.

One thing I am really interested to solve, is to somehow define a good way to
ready different types from a plain text table. For example if we can set an
internal Gnuastro standard to specify column datatypes, names and units in the
comments of a plain text table, then we can read a FITS binary table to a
plain text file, do some operations on it and save it back as a binary file
easily without the loss of information (like data types). Once we make a
robust enough library for this, all the utilities can read and write their
inputs and outputs to and from FITS tables if the user wants them too.

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