[R] Extracting only odd columns from a matrix

[Dimitris Rizopoulos]

one way is using the seq(), e.g., say 'm' is your matrix, then try:

m[, seq(1, ncol(m), by = 2)]


I hope it helps.

Best,
Dimitris


On 3/9/2011 3:20 PM, Nixon, Matthew wrote:
> Hi,
>
> This might seem like a simple question but at the moment I am stuck for ideas. The columns of my matrix in which some data is stored are of this form:
>
> X1     Y1     X2     Y2     X3     Y3     ...     Xn     Yn
>
> with n~100. I would like to look at just the X values (i.e. odd column numbers). Is there an easy way to loop round extracting only these columns?
>
> Any help would be appreciated.
>
> Thank you.
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-- 
Dimitris Rizopoulos
Assistant Professor
Department of Biostatistics
Erasmus University Medical Center

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