Creating a latex table from ftable object in R

Question

Let me create some data before I ask my question.

 my.data <- data.frame(A = sample(seq(1,100,by=5),10,replace=TRUE),W = rnorm(10),X =sample(1:10),Y = sample(c("yes", "no"), 10, replace = TRUE),Z=sample(c('a','b','c','d'),10,replace=TRUE))

attach(my.data)

my.d <- xtabs(W~Z+Y+A);my.d
table.data <- ftable(my.d)

result1 <- round(table.data,2)

result1 looks like ..

      A     6    11    16    26    71    76    86    91
Z Y                                                    
a no     0.00  0.00  0.00  0.00  0.00  0.00  0.00  0.00
 yes    0.00  0.56  0.00  0.00  0.00  0.79  0.00  0.01

b no     0.61  0.00 -0.22  0.14  0.00  0.00 -0.08  1.71
  yes    0.00  0.00  0.00  0.00  0.00  0.00  0.00  0.00

c no     0.00  0.00  0.00  0.00 -0.08  0.00  0.00  0.00
  yes    0.00  0.00  0.00  0.00  0.00  0.00  0.00  0.00

d no     0.00  0.00  0.00  0.00  1.00  0.00  0.00  0.00
  yes    0.00  0.00  0.00  0.00  0.00  0.00  0.00  0.00

I am actually writing an article using knitr package. Is there a way to transform result1 into a latex table automatically when my *.rnw file is complied ?

I tried with xtable but got the following error...

Error in UseMethod("xtable") :   no applicable method for 'xtable' applied to an object of class "ftable"

Thank you @DWin and @Yihui. Apart from latex(), I also used xtable as stated under

print(xtable(ftable2data.frame(result1)))

To remove unnecessary row names I did the following

print(xtable(ftable2data.frame(result1)),include.rownames=FALSE)

Answer 1

Method 1:

require(MIfuns)
require(Hmisc)
latex(ftable2data.frame(result1))

Answer 2

As an alternative, memisc provides toLatex methods for ftable objects.

library(memisc)
toLatex(result1)

Answer 3

You can use the package xtable:

library(xtable)
mytable=ftable(mydata)
print(
  xtable(format(mytable)),file="~/Desktop/mytable.tex"
)

I don't know how it compares to the other options given.

Answer 4

Building off of user2030503's answer,

# install.packages('simsalapar')
library(simsalapar)
utils::toLatex(result1)

The function toLatex is an S3 generic so passes to simsalapar:::toLatex.ftable() when given an ftable object. Alternatively you can just do simsalapar:::toLatex.ftable(result1).

Once that was done I needed to include \usepackage{booktabs} in the latex preamble as toLatex.ftable uses \toprule. Alternatively you can pass booktabs=FALSE.

It also looks like toLatex.ftable trims out trailing zeroes. To fix that this is what I did (see the answer to Formatting Decimal places in R for format()):

result1[1:nrow(result1),1:ncol(result1)] %<>% as.numeric %>% format(nsmall=2,digits=3)

this converts the matrix of the ftable to a character matrix, but toLatex.ftable still works.

I also found it helpful to \usepackage{pdflscape} and wrap my table with \begin{landscape} and \end{landscape} because these contingency tables can be quite wide.

Answer 5

Use the toLatex() function provided by the simsalapar Package.

library(simsalapar)
toLatex(result1)