lapply of list in ReporteRs packages

Question

I have a list of names and list of table which create in ReporteRs packages, called "MyFTable", I tried to apply list of MyFTable with list of t

t1 <- c("a","b","c")
t2 <- c("d","e","f")
t <- list(t1, t2)

If I do separately, it works, but when I put in the loop, it doesn't work.

  addHeaderRow(MyFTable[[1]], value=c("", t1))
  addHeaderRow(MyFTable[[2]], value=c("", t2))

This is my attempt:

  for(i in 1: length(MyFTable)){
  lapply(MyFTable[[i]],function(x) addHeaderRow(x, value=c("",t[[i]])))
}

for(i in 1: length(MyFTable)){
  lapply(MyFTable[[i]],function(x) addHeaderRow(x[[i]], value=c("",t[[i]])))
}

I got error :

x must be a FlexTable

Thanks for your advice.

Why are you `lapply`ing _in_ a `for`-loop? Use one or the other, and if you're going to use `for`-loops, preallocate. — alistaire, Jul 26 '16 at 18:34
I tried to apply the first list of df with the first list of name — BIN, Jul 26 '16 at 18:43

score 1 · Accepted Answer · answered Jul 26 '16 at 18:47

You are adding lapply for no good reason. You can do that in a regular loop.

out <- vector("list", length(MyFTable)) # always pre-allocate

for(i in 1:length(MyFTable)){
  out[[i]] <- addHeaderRow(MyFTable[[i]], value=c("",t[[i]])))
}

You can also use mapply which works on corresponding elements from all provided objects (in this case mft and tt).

myFun <- function(mft, tt) addHeaderRow(mft, tt)
mapply(FUN = myFun, mft = MyFTable, tt = t)

If you are hell-bent on lapply, you could "hide a loop".

lapply(1:length(MyFTable), FUN = function(i, mft, tt) {
  addHeaderRow(mft[[i]], value = c("", tt[[i]]))
}, mft = MyFTable, tt = t)

This last piece of code is interesting because it's easy to show how debugging works in R. By setting browser() at some point in a function, the execution will stop at that point and you can either inspect elements or advance by typing n or c. First command will move one line forward (from browser() call) and c will execute the current "loop" and wait at the browser() line in the next loop (if not finished, then it exists).

Try it, execute

lapply(1:length(MyFTable), FUN = function(i, mft, tt) {
  browser()
  addHeaderRow(mft[[i]], value = c("", tt[[i]]))
}, mft = MyFTable, tt = t)

and your prompt should change a bit. Inspect elements i, mft and tt and see if they match your MyFTable[[1]] and t[[1]] elements. To quit, type Q.

So if I have another function MyFTable[1,1:10, newpar=TRUE, to="header"]<- c("", second[[i]]) How it works for apply your function() — BIN, Jul 26 '16 at 18:58
I try for(i in 1:length(MyFTable)){MyFTable[[i]][1,1:10, newpar=TRUE, to="header"]<- c("", second[[i]])} it works — BIN, Jul 26 '16 at 19:01
@Stat at this point I will ask you to make a new question and provide a reproducible example. [Here are some tips](http://stackoverflow.com/questions/5963269/how-to-make-a-great-r-reproducible-example) on how to do just that. — Roman Luštrik, Jul 27 '16 at 04:37

lapply of list in ReporteRs packages

1 Answers1