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Expand.grid function for data.frames in R

I have 2 data.frames with the following columns.

1) A, B, C, D 2) E, F, G, H

What I would like to do is create a new data.frame that has a row for each expand.grid element (1 [, B] 2 [, F]) and will save all other columns and values ​​associated with the col B and col F values ​​from source data. frames

I am currently doing this using 2 for loops, and this creates a pretty long run time, since the data.frames I'm dealing with are pretty big.

Here is a screenshot of what I'm looking for:

> aa ABCD 1 1 x 3 5 2 2 y 4 6 > bb EFGH 1 7 j 9 11 2 8 k 10 12 > cc ABCDEFGH 1 1 x 3 5 7 j 9 11 2 2 y 4 6 7 j 9 11 3 1 x 3 5 8 k 10 12 4 2 y 4 6 8 k 10 12
+5
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4 answers

I think you are looking for:

 merge(aa,bb) ABCDEFGH 1 1 x 3 5 7 j 9 11 2 2 y 4 6 7 j 9 11 3 1 x 3 5 8 k 10 12 4 2 y 4 6 8 k 10 12
+8
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At some point, I adapted the code in expand.grid to simplify the grouping of column columns. Here is the code

 #available from #https://gist.github.com/MrFlick/00e2c589a2fa4b6d91f2 Expand.Grid<-function (..., stringsAsFactors = TRUE) { nargs <- length(args <- list(...)) if (!nargs) return(as.data.frame(list())) if (nargs == 0L) return(as.data.frame(list())) Names <- function(x) {if(!is.null(names(x))) names(x) else rep("",length(x))} Paste <- function(...) {a<-list(...); r<-do.call("paste", c(list(sep="."), a[sapply(a, function(x) !is.character(x) || any(nzchar(x)))])); nx <- max(sapply(a, length)) if (length(r)) return(rep(r, length.out=nx)) else return(rep("", nx)) } contribcols <- sapply(args, function(x) ifelse(class(x)=="data.frame", ncol(x), 1)) outargs <- sum(contribcols) cargs <- vector("list", outargs) nmc <- paste0("Var", seq.int(sum(contribcols))) nm <- unlist(lapply(seq_along(args), function(x) if(class(args[[x]])=="data.frame") { Paste(Names(args)[x], Names(args[[x]])) } else {Names(args)[x]})) if (is.null(nm)) nm <- nmc else if (any(ng0 <- !nzchar(nm))) nm[ng0] <- nmc[ng0] names(cargs) <- make.unique(make.names(nm)) rep.fac <- 1L d <- sapply(args, function(x) ifelse(class(x)=="data.frame", nrow(x), length(x))) orep <- prod(d) if (orep == 0L) { i<-1 for (a in seq_along(args)) { if (contribcols[a]==1) { args[[a]]=list(a) } for(j in seq_len(contribcols[a])) { cargs[[i]] <- args[[a]][[j]][FALSE] i <- i+1 } } } else { i<-1 for (a in seq_along(args)) { nx <- d[a] orep <- orep/nx x<-args[[a]] if (contribcols[a]==1) { x<-list(x) } for(j in seq_len(contribcols[a])) { y <- x[[j]] y <- y[rep.int(rep.int(seq_len(nx), rep.int(rep.fac, nx)), orep)] if (stringsAsFactors && !is.factor(y) && is.character(y)) y <- factor(y, levels = unique(y)) cargs[[i]] <- y i <- i+1 } rep.fac <- rep.fac * nx } } rn <- .set_row_names(as.integer(prod(d))) structure(cargs, class = "data.frame", row.names = rn) }

And then you can use it as

 aa<-read.table(text=" ABCD 1 1 x 3 5 2 2 y 4 6", header=T) bb<-read.table(text=" EFGH 1 7 j 9 11 2 8 k 10 12", header=T) Expand.Grid(aa,bb) # ABCDEFGH # 1 1 x 3 5 7 j 9 11 # 2 2 y 4 6 7 j 9 11 # 3 1 x 3 5 8 k 10 12 # 4 2 y 4 6 8 k 10 12

It also allows for additional combinations not directly related to this issue, such as

 #combine any number of data.frames and atomic vectors Expand.Grid(aa,other=1:2, bb) #give columns a prefix Expand.Grid(x=aa,y=aa)
+4
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You can expand.grid line numbers:

 myg <- expand.grid(aa=1:nrow(aa),bb=1:nrow(bb)) cbind(aa[myg$aa,],bb[myg$bb,])

The string names as a result are a little ugly:

  ABCDEFGH 1 1 x 3 5 7 j 9 11 2 2 y 4 6 7 j 9 11 1.1 1 x 3 5 8 k 10 12 2.1 2 y 4 6 8 k 10 12
+4
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Copying the example above, the intersection function from the tidyr package will also do the trick.

 aa <- read.table(text = " ABCD 1 1 x 3 5 2 2 y 4 6", header = T) bb <- read.table(text = " EFGH 1 7 j 9 11 2 8 k 10 12", header = T) crossing(aa, bb)

gives

 Source: local data frame [4 x 8] ABCDEFGH (int) (fctr) (int) (int) (int) (fctr) (int) (int) 1 1 x 3 5 7 j 9 11 2 1 x 3 5 8 k 10 12 3 2 y 4 6 7 j 9 11 4 2 y 4 6 8 k 10 12
+2
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