[R] Gui editor / viewer for large data

[Andreas Borg]

Dear all,

I am searching for a possibility to view large data sets (e.g. stored in 
ffdf objects) in a GUI window in a memory-efficient way. So far I looked 
at gtkDfEdit (package RGtk2Extras) and gdf (package gWidgets). Both 
operate (as far as I can see) on data frames stored in memory. gtkDfEdit 
accepts an ff data frame as input, but there is a long delay before it 
shows up, so I presume the data is converted to an in-memory data.frame 
beforehand.

Ideal would be a solution similar to JTable in Java, where one can 
implement a 'table model' class with a method ("getValueAt" or sth. like 
that) that returns the value of the underlying data for a given table 
cell (by x and y coordinates). When the table is drawn, getValueAt() is 
called for each cell in the viewable area. Cells outside the viewable 
range are not queried, so there is no need to keep the whole data in 
memory - it can be fetched from disk or computed on demand.

Before I seriously consider coding a suitable function or class myself, 
I would like to ask you, the R community, if anyone knows of an existing 
solution. To summarize, I need
    - a scrollable spreadsheet-like GUI element to view and potentially 
edit data
    - which only loads as much of the data as it displays at one point 
in time,
    - thereby able to handle datasets that are too large to fit into 
main memory

Thanks for any suggestions,

Andreas

-- 
Andreas Borg
Medizinische Informatik

UNIVERSITÄTSMEDIZIN
der Johannes Gutenberg-Universität
Institut für Medizinische Biometrie, Epidemiologie und Informatik
Obere Zahlbacher Straße 69, 55131 Mainz
www.imbei.uni-mainz.de

Telefon +49 (0) 6131 175062
E-Mail: borg at imbei.uni-mainz.de

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