R xtable: Wrap overflowing columns into subtables

Question

This question is related to the one here, but I feel that the solutions provided there don't answer the question.

My question is nearly the same. In R, I have the following aggregated data table:

> agg2
       x1.Err     x1.Pct       x2.Err     x2.Pct       x3.Err     x3.Pct      x4.Err     x4.Pct        x5.Err     x5.Pct     x6.Err
1 S.noun_noun 0.13121019  S.noun_noun 0.19791667  S.noun_noun 0.16730769 S.noun_noun 0.17659574  S.noun_noun 0.18352941 S.noun_noun
2 S.verb_verb 0.12611465  S.verb_verb 0.13750000  S.verb_verb 0.14615385 S.verb_verb 0.14042553  S.verb_verb 0.13176471 S.verb_verb
3   S.det_det 0.04076433    S.det_det 0.04375000    S.det_det 0.05384615 S.prep_prep 0.04042553 S.coord_prep 0.04000000 S.prep_prep
4 S.verb_noun 0.03821656    S.prn_prn 0.03958333 S.coord_prep 0.04423077   S.prn_prn 0.03829787    S.det_det 0.04000000   S.det_det
5  S.prep_det 0.03312102 S.coord_prep 0.03750000  S.prep_prep 0.04230769   S.det_det 0.03617021   S.prep_det 0.03764706   S.prn_prn
      x6.Pct      x7.Err     x7.Pct       x8.Err     x8.Pct
1 0.16839378 S.noun_noun 0.18330309  S.noun_noun 0.18281536
2 0.14766839 S.verb_verb 0.14700544  S.verb_verb 0.13893967
3 0.04663212   S.det_det 0.03811252   S.verb_prn 0.03839122
4 0.03886010   S.prn_prn 0.03448276  S.verb_noun 0.03656307
5 0.03108808 S.verb_prep 0.03448276 S.coord_prep 0.03473492

Displaying the data frame in R overflows, so definitely won't fit in a latex document. In my example, I can assume that splitting this into two "subtables" with 8 columns each would fit on my page.

 print(xtable(agg2, caption=My awesome caption, 
             label="tbl:myTable", digits=3))

How can I force my "table" to actually be 2 sub-tables with 8 columns each? In other words, how can I force the output to make n sub-tables with a maximum of k columns each? (n would be decided by the function, not the user)

Note: I do not want my table to be printed sideways. And to prevent over-complicating the Q&A, I'm not considering the possibility that the table will span multiple pages.

vaettchen vaettchen · Accepted Answer · 2015-07-08T12:07:00

This does no error checking, and you have to determine the number of columns manually, but it should give you a starting point. Edited to produce sub-tables, as I understand it.

# define a function that takes two parameters:
# - your long data.frame 
# - the number of columns you want to print in one table
varTable <- function( agg, cols ) 
{
  tables <- ceiling( length( agg ) / cols )    # number of tables to produce
  # list, first element is number of sub-tables
  p <- list( tables )
  # produce as many table as needed with the full number of columns
  for( i in 0 : ( tables - 2 ) ) p[[ i + 2 ]] <- xtable( agg[ ( cols * i + 1):( cols * i + cols ) ] )
  # last table may have less columns and takes the caption
  p[[ i + 3 ]] <- xtable( agg[ ( cols * ( i + 1  ) + 1):( length( agg ) ) ], caption = "bla" )
  # return the list with xtable objects that can now be printed one by one
  return( p )
}

Call the function

aggs <- varTable( agg2, 6 )

and print it altogether with

for( i in 2 : ( aggs[[ 1 ]] + 1 ) ) print( aggs[[ i ]], hline.after = 0 )

This gives me enter image description here

R xtable: Wrap overflowing columns into subtables

1 Answers