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[gov2001-l] Extracting rows/columns from a matrix

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Adam_Thomas＠ksgphd.harvard.edu

26 Feb 2003 26 Feb '03

12:45 a.m.

Hello all, Can anyone tell me how to extract a row or a column from a matrix? For instance, if I had a 10*4 matrix and wanted to create a vector containing only the 10 elements from the second column, what command(s) would I use? Thanks, Adam

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olau＠fas.harvard.edu

26 Feb 26 Feb

12:57 a.m.

Let's say X is your matrix. assigned.object <- X[,2] X[row, column] is the more general form. You can also extract a series of rows or columns: X[start.row:end.row,]. It's 1am. I'm hungry. Olivia. On Wed, 26 Feb 2003 Adam_Thomas(a)ksgphd.harvard.edu wrote:

Hello all, Can anyone tell me how to extract a row or a column from a matrix? For instance, if I had a 10*4 matrix and wanted to create a vector containing only the 10 elements from the second column, what command(s) would I use? Thanks, Adam _______________________________________________ gov2001-l mailing list gov2001-l(a)fas.harvard.edu http://www.fas.harvard.edu/mailman/listinfo/gov2001-l

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ravishan＠fas.harvard.edu

12:58 a.m.

I think you can use something like: x <- y[,2] where y is the 10*4 matrix and x is a vector. More generally, for one row: x <- y[row_num,] for one column: x <- y[, col_num] On Wed, 26 Feb 2003 Adam_Thomas(a)ksgphd.harvard.edu wrote:

Hello all, Can anyone tell me how to extract a row or a column from a matrix? For instance, if I had a 10*4 matrix and wanted to create a vector containing only the 10 elements from the second column, what command(s) would I use? Thanks, Adam _______________________________________________ gov2001-l mailing list gov2001-l(a)fas.harvard.edu http://www.fas.harvard.edu/mailman/listinfo/gov2001-l

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rtmoore＠fas.harvard.edu

1:03 a.m.

Adam: If the matrix is A, y <- A[,2] would store the second column of A as y. Ryan ------------------------------------------ Ryan T. Moore ~ Government & Social Policy Ph.D. Candidate ~ Harvard University On Wed, 26 Feb 2003 Adam_Thomas(a)ksgphd.harvard.edu wrote:

Hello all, Can anyone tell me how to extract a row or a column from a matrix? For instance, if I had a 10*4 matrix and wanted to create a vector containing only the 10 elements from the second column, what command(s) would I use? Thanks, Adam _______________________________________________ gov2001-l mailing list gov2001-l(a)fas.harvard.edu http://www.fas.harvard.edu/mailman/listinfo/gov2001-l

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Adam_Thomas＠ksgphd.harvard.edu
olau＠fas.harvard.edu
ravishan＠fas.harvard.edu
rtmoore＠fas.harvard.edu