cbind values to sublists in R

Question

I have two matrices in a list:

colList <- list()
colList[["V1"]] <- as.matrix(c("asd", "asd", "asd"))
colList[["V2"]] <- as.matrix(c("das", "das", "das"))

And I want to cbind the values of a data.frame value.frame$keyID to each sublist. The first value (2000) to the first sublist, the second value (3000) to the second sublist.

Here the value.frame:

value.frame <- data.frame(keyID =c("2000", "3000"))

The result should look like this:

colList <- list()
colList[["V1"]] <-  matrix(c("asd", "asd", "asd", 2000, 2000, 2000), 
                                nrow=3, 
                                ncol=2)

colList[["V2"]] <-  matrix(c("das", "das", "das", 3000, 3000, 3000), 
                               nrow=3, 
                               ncol=2)

I tried it with the following code, but the result is not the desired one. Hope someone can help me.

mapply( cbind, colList, paste(value.frame[,1]))

score 2 · Accepted Answer · answered Aug 27 '15 at 11:33

2

Using lapply and seq_along

nms <- names(colList)
colList <- lapply(seq_along(colList), x=colList,
   y=as.character(value.frame$keyID), function(j, x, y) {
  cbind(x[[j]], y[j])
})

names(colList) <- nms
colList[["V1"]]
     [,1]  [,2]  
[1,] "asd" "2000"
[2,] "asd" "2000"
[3,] "asd" "2000"

colList[["V2"]] 
     [,1]  [,2]  
[1,] "das" "3000"
[2,] "das" "3000"
[3,] "das" "3000"

answered Aug 27 '15 at 11:33

Whitebeard

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perfect! Thank you very much! – OAM Aug 27 '15 at 11:51

score 2 · Answer 2 · answered Aug 27 '15 at 12:58

You could do this with mapply using the option SIMPLIFY=FALSE

mapply(cbind, colList, as.character(value.frame$keyID), SIMPLIFY=FALSE)
#$V1
#     [,1]  [,2]  
#[1,] "asd" "2000"
#[2,] "asd" "2000"
#[3,] "asd" "2000"

#$V2
#     [,1]  [,2]  
#[1,] "das" "3000"
#[2,] "das" "3000"
#[3,] "das" "3000"

Or using Map which is a wrapper for mapply(..., SIMPLIFY=FALSE)

Map(cbind, colList, as.character(value.frame$keyID))

cbind values to sublists in R

2 Answers2