update.formula has 512 char buffer?

Your code seems to be screwed up. There are no (small) size
limitations on formulas (afaik).

The following worked fine for me:

x<- paste("x",1:100,sep="",collapse = " + ")
part1<- paste("y",x,sep=" ~ ")
part2<- paste("f",1:50, sep="",collapse = " + ")
fml<- formula(paste(part1,part2,sep=" | "))

Cheers,
Bert

On Tue, Feb 28, 2012 at 11:11 AM, Chris Hane
<christopher.a.hane at gmail.com>  wrote:

 Hello,

 I am trying to "paste" together a formula to use in the mob function of
 party. This means the formula will be of the form y ~ x1+ ...+xM | z1+..zN.

 I am doing some preliminary fits of y ~ x1+ ...+xM, then want to add the
 conditional part of the equation using update().

 Here's the test code:
 var1<- 1:78
 x1<- paste("x", var1, sep="")
 f1<- paste("f", var1[1:10], sep="")

 # use first 77 variables
 fmla<- as.formula( paste("y ~ ", paste(x1[1:77], collapse=" + ", sep=""),
 sep=""))
 fmla2<- update(fmla, paste(". ~ . | ", paste(f1, collapse= " + "), sep=""))

 # CHANGE x to all 78 variables
 fmla<- as.formula( paste("y ~ ", paste(x1, collapse=" + ", sep=""),
 sep=""))
 fmla2<- update(fmla, paste(". ~ . | ", paste(f1, collapse= " + "), sep=""))

 I have run this in Windows and Linux (64 bit) and both fail when using all
 78 terms (and anything more than 78 terms). The error message contains
 Error in parse(text = x) : :1:514: unexpected ')'.

 Changing the length of the names of the x variables will break the update()
 with fewer variables, but always with an error referring to just more than
 512 characters.  There is nothing special about 77 or 78 variables here; I
 want to do this with hundreds of variables.

 Is there a workaround to this?

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