[R] Building a formula using paste

Fri Feb 1 13:06:35 CET 2008

Thank you very much. That problem has been niggling me for some time. 

I slotted in your code and it worked. I just need to spend a bit of time
understanding it ...

Thanks again.

John Seers

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-----Original Message-----
From: Bill.Venables at csiro.au [mailto:Bill.Venables at csiro.au] 
Sent: 01 February 2008 09:57
To: Bill.Venables at csiro.au; john seers (IFR); r-help at stat.math.ethz.ch
Subject: RE: [R] Building a formula using paste

Please disregard my previous reply.  Now that I have read your question,
all becomes clear.

To do what you want to do is a bit tricky.  Here is one way

f1 <- as.name("F1")
fm <- eval(bquote(aov(.(f1) ~ sensoryTerm, data = vdata)))

Them fm is the fitted model object, suitably formed.

E&OE, of course! 

Bill Venables
CSIRO Laboratories
PO Box 120, Cleveland, 4163
AUSTRALIA
Office Phone (email preferred): +61 7 3826 7251 Fax (if absolutely
necessary):  +61 7 3826 7304
Mobile:                         +61 4 8819 4402
Home Phone:                     +61 7 3286 7700
mailto:Bill.Venables at csiro.au
http://www.cmis.csiro.au/bill.venables/ 

-----Original Message-----
From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org]
On Behalf Of Venables, Bill (CMIS, Cleveland)
Sent: Friday, 1 February 2008 7:45 PM
To: john.seers at bbsrc.ac.uk; r-help at stat.math.ethz.ch
Subject: Re: [R] Building a formula using paste

use as.formula() rather than just formula(). 

Bill Venables
CSIRO Laboratories
PO Box 120, Cleveland, 4163
AUSTRALIA
Office Phone (email preferred): +61 7 3826 7251 Fax (if absolutely
necessary):  +61 7 3826 7304
Mobile:                         +61 4 8819 4402
Home Phone:                     +61 7 3286 7700
mailto:Bill.Venables at csiro.au
http://www.cmis.csiro.au/bill.venables/ 

-----Original Message-----
From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org]
On Behalf Of john seers (IFR)
Sent: Friday, 1 February 2008 7:31 PM
To: r-help at stat.math.ethz.ch
Subject: [R] Building a formula using paste

Hi All

I have looked but cannot find an answer to this.

I want to build a formula dynamically (in a function), using for example
paste, and using it in a model:

	fr<-"F1"	
  	f1<-formula(paste(fr, "~ SensoryTerm"))
  	m1<-aov(f1, data=vdata)

So this is the equivalent of m1<-aov(F1 ~ SensoryTerm, data=vdata)

This works fine but the problem is the formula appears as "f1" in the
summary(m1) of the model and not "F1 ~ SensoryTerm". With many models
this can be a bit confusing ....

Is there a way to code this so the formula appears in the model summary?

Regards

John Seers

> sessionInfo()
R version 2.6.1 (2007-11-26)
i386-pc-mingw32 

locale:
LC_COLLATE=English_United Kingdom.1252;LC_CTYPE=English_United
Kingdom.1252;LC_MONETARY=English_United
Kingdom.1252;LC_NUMERIC=C;LC_TIME=English_United Kingdom.1252

attached base packages:
[1] stats     graphics  grDevices datasets  utils     methods   base

other attached packages:
 [1] pixmap_0.4-7  gplots_2.3.2  gdata_2.3.1   gtools_2.4.0
rcom_1.5-2.2 
 [6] nnet_7.2-38   e1071_1.5-17  class_7.2-38  tree_1.0-26   mgcv_1.3-29

[11] MASS_7.2-38   car_1.2-7     RODBC_1.2-2   RWinEdt_1.7-9
> 

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