data.table error when used through knitr, gWidgetsWWW

Question

I\'m experimenting with gWidgetsWWW and encountered a strange error. I created a button with a handler to knit2html a report which used the data.table assignment operator \"

Answer 1

This seems to be an environment issue. That is probably a problem between data.table and gWidgetsWWW. On knitr's side, there is at least one solution, which is to specify the environment for knitr to be the global environment, e.g.

knit2html("test_report.Rmd", envir = globalenv())

Edit:

To illustrate this issue is irrelevant to knitr, try this:

library(gWidgetsWWW)

w<-gwindow("Test Window")
g<-ggroup(horizontal=F,cont=w)
b<-gbutton("Report Button",cont=g,handler=function(h,...){
  library(data.table)
  df<-data.frame(State=rownames(USArrests),USArrests)
  print(data.table(df)[,State:=tolower(State)])
})

visible(w)<-TRUE

Save it as test_gui.R, and

library(gWidgetsWWW)
localServerOpen('test_gui.R')

Click the button and you will also see the error.