On 30-Sep-03 Rajarshi Guha wrote:...
Hi, I'm trying to take a set of rows and columns out of a matrix. I hve been using the index aray approach. My overll matrix is X and is 179 x 65. I want to take out 4 columns and 161 rows.
This is documented in "An Introduction to R", under the section "Arrays and Matricies". There's lots of good stuff in there. From R:
help.start()
And click on "An Introduction to R".
The short answer to this particular question:
a) negative indicies remove rows or columns. Since you only want to remove 4 columns, I'd use that.
b) Since you only want to keep 18 rows, I'd use the numbers of the rows you want to keep.
As a toy example, say you wanted to remove columns 51 to 54, and keep the last 18 rows:
newX <- X[162:179,-(51:54)]
There's even more handy stuff in the document mentioned above.
cheers
Jason -- Indigo Industrial Controls Ltd. http://www.indigoindustrial.co.nz 64-21-343-545 [EMAIL PROTECTED]
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