Click on row in TextArea?

I have a GUI that contains a TextArea. I read in a file that is 20,000 x 16 and convert each row to a string, so the resulting table is 20,000 x 1. Then I read that new "fits_text" table into the TextArea and use a formatSpec string to display it in neat columns, using tabs.

fits.TextArea.Value = fits_text;

So far, so good. Is there a way to click on a row of the text and determine which row it was, so I can process the data at that row in my original table (which is 20000 x 16)? Or do I need to use a UITable instead? I'm not sure I can fit a 16-column UITable into this GUI window.

Bonus question: It takes me about 7 minutes to re-format all 20,000 rows for display, using a "for" loop. I am pre-allocating space for the table. There must be a faster way. I can do this in Python in just a few seconds (but it doesn't look nearly as nice).

for i = 1:height(box_data)
    fits_text{i,1} = sprintf(formatSpec, string(box_data{i,:}));
end

Answer 1

[Kurt]

The "compose" approach reduced the formatting from about 7 minutess to 10 seconds. Thanks!

I solved the TextArea size issue by leaving the 16-column TexArea alone, and creating a separate UITable off to the side containing just the first column of the TextArea - in effect, a "spinbox" containing text, not numbers. I can scroll through it and pick the appropriate line by clicking.

Answer 2

[Walter Roberson]

Unfortunately, TextArea do not have any selection callbacks; https://www.mathworks.com/help/matlab/ref/matlab.ui.control.textarea-properties.html

For the performance issue: use https://www.mathworks.com/help/matlab/ref/table.convertvars.html to build a new table from converting the existing variables to string. Then if you

fmt = [repmat('%s ', 1, 15), '%s'];
fits_text = compose(string(fmt), Table_Of_Strings{:,:});

This should, in theory, be higher performance.

If you wanted more careful control over the conversion of items into string then

fits_text = compose("Detailed % formats", box_data{:,1}, box_data{:,2}, box_data{:,3} ... box_data{:,16})

an uglier command line to be sure, but it gives per-item control like %6.2f and %-10s

[Kurt]

Thanks. I'll try that.

Back to the performance issue: Is there a method to apply a full-blown function to an entire column without looping? I run into this a lot. I've done the simple one-liner, inline functions on a whole column, but I need something more. For example, the code to convert azimuth to right ascension is about 50 lines long. Is this possible?

[Walter Roberson]

arrayfun.... but it is just a hidden loop, and you are better off vectorizing the code, possibly using logical indexing.