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st: RE: Keeping the upper triangle of a matrix.
From
Nick Cox <[email protected]>
To
"'[email protected]'" <[email protected]>
Subject
st: RE: Keeping the upper triangle of a matrix.
Date
Thu, 20 Jan 2011 18:26:19 +0000
Sounds like
keep if var1 <= var2
Nick
[email protected]
Philipp Krueger
I am a bit stuck. I have the following dataset
var1; var2; var3
1; 1; aaa
1; 2; def
1; 3; ghi
2; 1; def
2; 2; aaa
2; 3; klm
3; 1; ghi
3; 2; klm
3; 3; aaa
Essentially, the three row vectors of a 3x3 matrix are stacked
underneath each other in a dataset. Since the matrix is symmetric, I
would like to keep only the observations corresponding to the lower
triangle of the matrix (including the diagonal), i.e. observations
1,2,3,5,6,9 in the dataset. All other observations (i.e. 4 and 8 should
be dropped. I have tried hard but could not find a solution.
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