Displaying 2 results from an estimated 2 matches for "rsub".
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2006 Feb 17
3
Matrix indexing in a loop
How do you specify matrix location a[i,j] (or a[i-1,j], etc.) in a "for"
loop?
I am looking for a flexible method of indexing neighbors over a series
of lags (1,2,3...) and I may wish to extend this method to 3D arrays.
Example:
Data matrix
> fun
[,1] [,2] [,3]
[1,] 1 5 9
[2,] 2 6 10
[3,] 3 7 11
[4,] 4 8 12
For each element a[i,j] in
2011 Oct 20
2
Aggregating data help
Hello,
I have a dataset with student performance on a math test. There are
multiple cases for each student (identified by id) and the concept as a
variable.
> rtest
id test subject grade concept correct tested per_corr
year
1 1 83 Mathema 8 8.2.D 1 1 100
2011
2 1 83 Mathema 8 8.3.A 1 2