Re: [R] Error with predict and newdata

2015-08-08 Thread David Winsemius

On Aug 7, 2015, at 2:41 PM, kira taylor wrote:

 Hi!
 
 I am trying to use predict to apply my model to data from one time period to
 see what might be the values for another time period.  I did this
 successfully for one dataset, and then tried on another with identical code
 and got the following error:
 
 Error in eval(predvars, data, env) :
  numeric 'envir' arg not of length one
 
 The only difference between the two datasets was that my predictor model for
 the first dataset had two predictor variables and my model for the second
 dataset had only one.  Why would this make a difference?
 
 My dougfir.csv contains just two columns with thirty numbers in each,
 labeled height and dryshoot.
 
 my lm is: fitdougfir - lm(dryshoot~height,data=dougfir)
 
 It gets a little complicated (and messy, sorry!  I am new to R) because I
 then made a second .csv - the one I used to make my model contained values
 from just June.  My new .csv (called alldatadougfir.csv) includes values
 from October as well, and also contains a date column that labels the
 values either june or october.
 
 I did the following to separate the height data by date:
 
 alldatadougfir[alldatadougfir$date==june,c(height)]-junedatadougfir
 alldatadougfir[alldatadougfir$date==october,c(height)]-
 octoberdatadougfir

Those are no longer lists or dataframe, which are the proper classes of object 
to pass to predict. 

-- 
David.
 
 I then want to use my June model to predict my October dryshoots using
 height as my variable and I did the following:
 
 predict(fitdougfir, newdata=junedatadougfir)
 predict(fitdougfir, newdata=octoberdatadougfir)
 
 Again, I did this with an identical dataset successfully - the only
 difference was that my model in the successful dataset had two predictor
 variables instead of the one variable (height) I have in this dataset.
 
 Sorry again for my messy code!
 
 Thank you very much,
 
 Kira
 
   [[alternative HTML version deleted]]
 
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David Winsemius
Alameda, CA, USA

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Re: [R] Error with predict and newdata

2015-08-08 Thread Ben Bolker
David Winsemius dwinsemius at comcast.net writes:

 
 
 On Aug 7, 2015, at 2:41 PM, kira taylor wrote:
 
  Hi!
  
  I am trying to use predict to apply my model to data from
  one time period to
  see what might be the values for another time period.  I did this
  successfully for one dataset, and then tried on another
  with identical code
  and got the following error:
  
  Error in eval(predvars, data, env) :
   numeric 'envir' arg not of length one
  

  Please don't cross-post on StackOverflow and the r-help lists
(it will usually lead to duplicated/wasted effort).  If you must,
at least post a link/indicate in each venue that you have cross-posted
to the other: 

(line-broken link, reassemble to visit)

http://stackoverflow.com/questions/31887043/
error-with-predict-and-newdata-dependent-on-number-of-
predictor-variable-in-mod/31887398#31887398

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and provide commented, minimal, self-contained, reproducible code.


[R] Error with predict and newdata

2015-08-07 Thread kira taylor
Hi!

I am trying to use predict to apply my model to data from one time period to
see what might be the values for another time period.  I did this
successfully for one dataset, and then tried on another with identical code
and got the following error:

Error in eval(predvars, data, env) :
  numeric 'envir' arg not of length one

The only difference between the two datasets was that my predictor model for
the first dataset had two predictor variables and my model for the second
dataset had only one.  Why would this make a difference?

My dougfir.csv contains just two columns with thirty numbers in each,
labeled height and dryshoot.

my lm is: fitdougfir - lm(dryshoot~height,data=dougfir)

It gets a little complicated (and messy, sorry!  I am new to R) because I
then made a second .csv - the one I used to make my model contained values
from just June.  My new .csv (called alldatadougfir.csv) includes values
from October as well, and also contains a date column that labels the
values either june or october.

I did the following to separate the height data by date:

alldatadougfir[alldatadougfir$date==june,c(height)]-junedatadougfir
alldatadougfir[alldatadougfir$date==october,c(height)]-
octoberdatadougfir

I then want to use my June model to predict my October dryshoots using
height as my variable and I did the following:

predict(fitdougfir, newdata=junedatadougfir)
predict(fitdougfir, newdata=octoberdatadougfir)

Again, I did this with an identical dataset successfully - the only
difference was that my model in the successful dataset had two predictor
variables instead of the one variable (height) I have in this dataset.

Sorry again for my messy code!

Thank you very much,

Kira

[[alternative HTML version deleted]]

__
R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
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.