[R] How to rbind() two matrices that have different column sizes?

[Noah Marconi]

Out of curiosity, what's the reason for not using plyr?

If it has to do with installing the package, here's how the rbind.fill 
function is implemented in plyr. It may help show you what you'd like to 
do:

> plyr::rbind.fill
function (...)
{
     dfs <- list(...)
     if (length(dfs) == 0)
         return()
     if (is.list(dfs[[1]]) && !is.data.frame(dfs[[1]])) {
         dfs <- dfs[[1]]
     }
     dfs <- compact(dfs)
     if (length(dfs) == 0)
         return()
     if (length(dfs) == 1)
         return(dfs[[1]])
     is_df <- vapply(dfs, is.data.frame, logical(1))
     if (any(!is_df)) {
         stop("All inputs to rbind.fill must be data.frames",
             call. = FALSE)
     }
     rows <- unlist(lapply(dfs, .row_names_info, 2L))
     nrows <- sum(rows)
     ot <- output_template(dfs, nrows)
     setters <- ot$setters
     getters <- ot$getters
     if (length(setters) == 0) {
         return(as.data.frame(matrix(nrow = nrows, ncol = 0)))
     }
     pos <- matrix(c(cumsum(rows) - rows + 1, rows), ncol = 2)
     for (i in seq_along(rows)) {
         rng <- seq(pos[i, 1], length = pos[i, 2])
         df <- dfs[[i]]
         for (var in names(df)) {
             setters[[var]](rng, df[[var]])
         }
     }
     quickdf(lapply(getters, function(x) x()))
}
<environment: namespace:plyr>
> plyr::quickdf
function (list)
{
     rows <- unique(unlist(lapply(list, NROW)))
     stopifnot(length(rows) == 1)
     names(list) <- make_names(list, "X")
     class(list) <- "data.frame"
     attr(list, "row.names") <- c(NA_integer_, -rows)
     list
}
<environment: namespace:plyr>


There's a stackoverflow discussion that covers another alternative using 
data.tables if that's preferable: 
http://stackoverflow.com/questions/18003717/is-there-any-efficient-way-than-rbind-filllist


It looks like dplyr has another alternative implemented in C++ as well: 
https://github.com/hadley/dplyr/blob/master/R/rbind.r



On 2014-03-26 10:06, Babak Bastan wrote:
> Hi friends
> 
> I would like to rbind two matrices with different column number. How 
> can I
> do that? (I dont want to use Plyr package). Is there any way except 
> plyr?
> 
> 	[[alternative HTML version deleted]]
> 
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