[R] forecast.lm() and NEWDATA

[PIKAL Petr]

Hi

> -----Original Message-----
> From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-
> project.org] On Behalf Of Ryan
> Sent: Monday, November 04, 2013 4:19 PM
> To: David Winsemius
> Cc: r-help at r-project.org
> Subject: Re: [R] forecast.lm() and NEWDATA
> 
> Hi David (and everyone)
> 
> Thank you for your reply.
> 
> I see I copied down the code wrong for the regression. I was using the
> "+" seperator, and not ",".  The regression was working.
> 
> I made a mistake with the NEWDATA, where I also used "+", instead of
> ",", however I see both work but return very different results. I have
> corrected the mistake.
> 
> However, I am still receiving the same error when I try to run the
> forecast.lm.
> "
> 
> forecast.lm(REGGY, h=5)
> 
> i receive the following error
> "Error in as.data.frame(newdata) :
>   argument "newdata" is missing, with no default""
> 

Where is forecast.lm from? Anyway, it probably requires an argument for newdata so maybe

forecast.lm(REGGY, newdata=somedata, h=5)

will work.

Regards
Petr

> 
> 
> I am sorry to say, I don't understand your reference to the string
> output when you mentioned
> 
> "
> 
> You should post the output of str() on the data-objects that has the 12
> variables and if it was modified the data argument pasted to `lm()`
> when you made REGGY.
> 
> "
>   As of right now, NEWDATA includes all the independent variables from
> the REGGY Regression.
> 
> 
> Should the NEWDATA data.frame include the dependent variable?
> 
> Also, is it necessary to reformat all variables as time series? (I have
> not currently done so)
> 
> Regards
> Ryan
> 
> On 2013-11-01 07:28 PM, David Winsemius wrote:
> > On Nov 1, 2013, at 6:50 AM, Ryan wrote:
> >
> >> Good day all.
> >>
> >> I am hoping you can help me (and I did this right). I've been
> working in R for a week now, and have encountered a problem with
> forecast.lm().
> >>
> >> I have a list of 12 variables, all type = double, with 15 data
> entries.
> >> (I imported them from tab delimited text files, and then formatted
> as.numeric to change from list to double)
> >> (I understand that this leaves me rather limited in my degrees of
> freedom, but working with what I have, sadly. )
> >>
> >> I have a LM model, such that
> >> REGGY = lm(formula=Y~A,B,C,...,I,J)
> > This looks wrong. Separating independent predictors with commas would
> be highly unusual.
> >> which I am happy with.
> >>
> >> I have
> >> NEWDATA = data.frame(A+B+C+D....+I+J)
> > This also looks wrong. Separating arguments to data.frame with "+"-
> signs is surely wrong.
> >> When i try to run
> >>
> >> forecast.lm(REGGY, h=5)
> >>
> >> i receive the following error
> >> "Error in as.data.frame(newdata) :
> >>   argument "newdata" is missing, with no default"
> > If your code prior to calling forecast on the REGGY-object was really
> what you showed here, I am not surprised. You should post the output of
> str() on the data-objects that has the 12 variables and if it was
> modified the data argument pasted to `lm()` when you made REGGY.
> (Beginners should name their data arguments.)
> >
> >> When I run
> >> forecast.lm(REGGY, NEWDATA, h=5)
> >> I receive the confidence intervals of the 15 data entries I already
> possess. I understand that by including NEWDATA, the "h=5" is ignored,
> but without NEWDATA, I receive the error message.
> >>
> >> Can anyone help me please?
> >>
> >> Regards
> >> Ryan
> >>
> >> P.S The forecast is trying to predict the next 5 values for Y from
> the regression model pasted above. I'm a bit rusty with regressions,
> but I think I've covered my bases as well as I can, and from what I
> understand of the R code, I'm following the right steps.
> > Not if what you posted here was your code. I think you missed a few
> crucials points about R syntax.
> 
> ______________________________________________
> R-help at r-project.org mailing list
> 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.