R help - Sep 2012 - How to insert vertical space between lines of tables created with the R package 'tables'?

I have the data frame...

df <- cbind(expand.grid(d=as.factor(c(2,5)), n=c(100, 200),
beta=as.factor(c(0.2, 0.8)), group=LETTERS[1:2]), value=runif(16))

... which I would like to display in a table like ...

require(tables)
tabular(d * beta ~ group * mean * Heading() * value, data=df)

Now I would like to insert (vertical) space between every other line of the
table. I checked the manual and vignette of 'tables', but it only covers
the
case when there is just one variable specified in the left-hand side of the
formula (so "to the left" of "~"). I tried to adapt the idea
of using
RowFactor() ... 

tabular(RowFactor(1:4, "", spacing=2, space=0.5) + d * beta ~ group *
mean *
Heading() * value, data=df)

... but obtain ... 

Error in `colnames<-`(`*tmp*`, value = "") : 
  length of 'dimnames' [2] not equal to array extent


Cheers,

Marius

On 12-09-08 11:41 AM, Marius Hofert wrote:
> I have the data frame...
>
> df <- cbind(expand.grid(d=as.factor(c(2,5)), n=c(100, 200),
> beta=as.factor(c(0.2, 0.8)), group=LETTERS[1:2]), value=runif(16))
>
> ... which I would like to display in a table like ...
>
> require(tables)
> tabular(d * beta ~ group * mean * Heading() * value, data=df)
>
> Now I would like to insert (vertical) space between every other line of the
> table. I checked the manual and vignette of 'tables', but it only
covers the
> case when there is just one variable specified in the left-hand side of the
> formula (so "to the left" of "~"). I tried to adapt the
idea of using
> RowFactor() ...
>
> tabular(RowFactor(1:4, "", spacing=2, space=0.5) + d * beta ~
group * mean *
> Heading() * value, data=df)
>
> ... but obtain ...
>
> Error in `colnames<-`(`*tmp*`, value = "") :
>    length of 'dimnames' [2] not equal to array extent

The + means concatenation, so that spec says to put the RowFactor above 
the d*beta rows.  Not sure why that causes an error, but it's likely 
because you've got the wrong number of items.

This should work, but it doesn't give you the extra spacing properly. I 
didn't think anyone would want extra spacing on every level.  I'll put 
in a patch to fix it; look for an update on R-forge.

tabular(RowFactor(d, spacing=1, space=0.5) * beta ~ group * mean *
+ Heading() * value, data=df)


Duncan Murdoch