cbind a dataframe with an empty dataframe - cbind.fill?

Question

I think I'm looking for an analog of rbind.fill (in Hadley's plyr package) for cbind. I looked, but there is no cbind.fill.

What I want to do is the following:

#set these just for this example one_option <- TRUE diff_option <- TRUE  return_df <- data.frame()  if (one_option) {     #do a bunch of calculations, produce a data.frame, for simplicity the following small_df     small_df <- data.frame(a=1, b=2)     return_df <- cbind(return_df,small_df) }  if (diff_option) {     #do a bunch of calculations, produce a data.frame, for simplicity the following small2_df     small2_df <- data.frame(l="hi there", m=44)     return_df <- cbind(return_df,small2_df) }  return_df 

Understandably, this produces an error:

Error in data.frame(..., check.names = FALSE) :  arguments imply differing number of rows: 0, 1 

My current fix is to replace the line return_df <- data.frame() with return_df <- data.frame(dummy=1) and then the code works. I then just remove dummy from the return_df at the end. After adding the dummy and running the above code, I get

      dummy a b        l  m 1     1 1 2 hi there 44 

I then just need to get rid of the dummy, e.g.:

> return_df[,2:ncol(return_df)]   a b        l  m 1 1 2 hi there 44 

I'm sure I'm missing an easier way to do this.

edit: I guess I'm not looking for a cbind.fill because that would mean that an NA value would be created after the cbind, which is not what I want.

Answer 1

Here's a cbind fill:

cbind.fill <- function(...){     nm <- list(...)      nm <- lapply(nm, as.matrix)     n <- max(sapply(nm, nrow))      do.call(cbind, lapply(nm, function (x)          rbind(x, matrix(, n-nrow(x), ncol(x)))))  } 

Let's try it:

x<-matrix(1:10,5,2) y<-matrix(1:16, 4,4) z<-matrix(1:12, 2,6)  cbind.fill(x,y) cbind.fill(x,y,z) cbind.fill(mtcars, mtcars[1:10,]) 

I think I stole this from somewhere.

EDIT STOLE FROM HERE: LINK

Answer 2

While, I think Tyler's solution is direct and the best here, I just provide the other way, using rbind.fill() that we already have.

require(plyr) # requires plyr for rbind.fill() cbind.fill <- function(...) {                                                                                                                                                          transpoted <- lapply(list(...),t)                                                                                                                                                    transpoted_dataframe <- lapply(transpoted, as.data.frame)                                                                                                                            return (data.frame(t(rbind.fill(transpoted_dataframe))))                                                                                                                           }