Duplicating recurring rows

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Hey folks,

I'm new to the forum, but I will likely become a fixture here. Igor is a new program for me, but my line of grad work requires its use daily. Thanks for fielding my question!

I'm trying to duplicate specific rows from an existing wave into a new wave. For example, say I have 200 rows of data in 4 waves. I would like to put every tenth value from wave1 into a new wave....

How do I go about that?

Thanks!
so far, I've found this in the manual. however, it's still unclear how to choose every tenth value...

wave1[1,*;2] = 100 // sets every odd point of wave0

August 24, 2011 at 02:25 pm - Permalink
extract originalWave,resultWave,mod(p,10)==0 will probably do what you want.

A

August 24, 2011 at 02:57 pm - Permalink
Hmm, I think this will do the job, too:
To extract every tenth value make a wave which has n/10 rows (20 in your case):

make/n=20 newwave

Then use the row counter 'p' in the expression (will count through all rows of newwave, i.e. 0....19):

newwave = wave1[10*(p+1)] // extract point 10, 20, 30, 40, ...

August 25, 2011 at 02:37 am - Permalink
[quote=chozo]newwave = wave1[10*(p+1)] // extract point 10, 20, 30, 40, ...[/quote]

Of course this works as well as my approach. Just be carefull with indexing on the right side of the equation. Your example doesn't extract a value from the first 10 points of wave1 and in return two values from the last 10 points of wave1. Used in a user-defined function compiled with #pragma rtGlobals=3, it would actually throw an error, because the index runs to 200.
Use newwave = wave1[10*p+j] where j is the first point that gets extracted and should be from the interval [0,9]. So choose j=0 (or omit j) if you want to extract points 0, 10, 20, 30, ..., or j=1 to extract the points 1, 11, 21, 31, ..., etc.

A

August 25, 2011 at 05:43 am - Permalink