taskGNU Astronomy Utilities - Tasks: task #14986, Match: Include columns with no...


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task #14986: Match: Include columns with no match in output

Submitter:  Mohammad Akhlaghi <makhlaghi>
Submitted:  Mon 16 Jul 2018 10:01:02 PM UTC
Should Start On:  Sun 15 Jul 2018 10:00:00 PM UTC Should be Finished on:  Sun 15 Jul 2018 10:00:00 PM UTC
Category:  Match Priority:  5 - Normal
Item Group:  Enhancement Status:  Postponed
Privacy:  Public Assigned to:  makhlaghi
Percent Complete:  70% Open/Closed:  Open
Effort:  0.00

Sun 27 Jun 2021 03:19:09 AM UTC, comment #1: 

With Commit 0fc33aa193 it is now possible to construct the output by adding non-matching rows of second input to all the rows of the first input. Therefore allowing easy merging of many catalogs into one, without having any repetition.

When both inputs have the same number of columns and same column names and same column data types (for each same name), it is possibly to simply use '--outcols=_all' to fully merge non-matching rows of both tables into one.

However, currently, it doesn't allow differing columns: It doesn't add extra columns to each table (and fill them with blanks where necessary) as Juan had original proposed. So the task isn't 100% complete.

The most recent Gnuastro book and tarball (that implement this feature) are available in the links below. For more on this new feature, see the description of '--outcols' in the Match program of the book below (on page 369-370 as of this commit).


Mohammad Akhlaghi <makhlaghi>
Group administrator
Mon 16 Jul 2018 10:01:02 PM UTC, original submission:  

Juan Molina: "Try to add a flag to the match procedure in which the non-matched sources are added as additional ‘rows’ in the final catalog file. But at the same moment keeping the useful information from the two original catalogs (i.e., by adding new columns to the new catalog file). The objects with no information in some columns may have assigned a “nan” value."

This is a very useful suggestion to allow users to ask Match to build a combined table that is larger than the two individual inputs. This allows building up of a large collection of catalogs where some rows match and some don't, but all will be kept.

Mohammad Akhlaghi <makhlaghi>
Group administrator


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    Follow 3 latest changes.

    Date Changed by Updated Field Previous Value => Replaced by
    2021-06-27 makhlaghi Percent Complete0% 70%
        Assigned toNone makhlaghi
    2018-07-16 makhlaghi Carbon-Copy- Added -email is unavailable-

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