Re: [R] Constructing dummy variables for months for a time series object

From: Gabor Grothendieck <ggrothendieck_at_gmail.com>
Date: Fri, 25 Apr 2008 19:32:59 -0400

First generate a factor and then calculate its model matrix:

month. <- factor(cycle(x), labels = month.abb) model.matrix(~ month.)[,-1]

Actually you may not even need the dummy variables at all if your purpose is to do a regression. You can use the factor directly:

lm(x ~ month.)

By the way, be sure to check out ?monthplot

On Fri, Apr 25, 2008 at 3:40 AM, Megh Dal <megh700004_at_yahoo.com> wrote:
> I have a TS of monthly observations.
>
> head(data4)
> 1991(1) 1991(2) 1991(3) 1991(4) 1991(5) 1991(6)
> 12.00864 11.94203 11.98386 12.01900 12.19226 12.15488
>
> Now I want to make 11 dummy variables indicating months. Therefore I did followings :
>
> For Jan :
> rep(c(rep(0,0), 1, rep(0, 11)), 17)
>
> For Feb :
> rep(c(rep(0,1), 1, rep(0, 10)), 17)
>
> ........ and so on
>
> But my question is there any way to aumate this? Or I have to do the above thing for all 11 months?
>
>
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https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code. Received on Fri 25 Apr 2008 - 23:58:31 GMT

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