Failing to print mer object in an RData image

Have you load lme4 before you print the object?

If yes, it may be caused by the change of representation of "mer" class.

2009/4/23 Robert Zimbardo <robertzimbardo at gmail.com>:

Hi all

I have problems in accessing a mer object called model.01 from a
workspace that was created with R 2.8.1 and saved with save into an
.RData file (on Windows XP or Ubuntu 8.10, don't remember anymore).
Now I want to open it in R 2.9.0 on Ubuntu 8.10. I use

# load workspace
load("name.RData")

which seems to work:

ls() # all objects in there
[1] "all" ? ? ? ? ?"all.dd" ? ? ? "model.01" ? ? "model.sorter"

It also recognizes the class of model.01:

class(model.01)

[1] "mer"
attr(,"package")
[1] "lme4"

But when I want to print it or look at its structure:

print(model.01)
Error in slot(value, what) :
?no slot of name "Xst" for this object of class "mer"

str(model.01)

Error in FUN(c("env", "nlmodel", "frame", "call", "flist", "X", "Xst", ?:
?no slot of name "Xst" for this object of class "mer"

Any idea what to do?

R.version

platform ? ? ? i486-pc-linux-gnu
arch ? ? ? ? ? i486
os ? ? ? ? ? ? linux-gnu
system ? ? ? ? i486, linux-gnu
status
major ? ? ? ? ?2
minor ? ? ? ? ?9.0
year ? ? ? ? ? 2009
month ? ? ? ? ?04
day ? ? ? ? ? ?17
svn rev ? ? ? ?48333
language ? ? ? R
version.string R version 2.9.0 (2009-04-17)

library(help=lme4)

Package: ? ? ? lme4
Version: ? ? ? 0.999375-28
Date: ? ? ? ? ?2008-12-13

Thanks,
RZ

--
HUANG Ronggui, Wincent
PhD Candidate
Dept of Public and Social Administration
City University of Hong Kong
Home page: http://asrr.r-forge.r-project.org/rghuang.html