rbinding two columns together in a dataframe

Question

I have:

col 1,  col2,  col3,   col4     val
 a       b       c       d       5
 f       g       h       i       6
...

I want to rbind two columns together. I have the following:

newcol1,    newcol2
  a           b
  c           d
  f           g
  h           i
 ...

score 4 · Answer 1 · answered Jan 02 '21 at 23:31

4

Here is a data.table option using rbindlist

data.table::rbindlist(split.default(df, ceiling(seq_along(df) / 2)), use.names = FALSE)

which gives

   col1 col2
1:    a    b
2:    f    g
3:    c    d
4:    h    i

Data

> dput(df)
structure(list(col1 = c("a", "f"), col2 = c("b", "g"), col3 = c("c", 
"h"), col4 = c("d", "i")), class = "data.frame", row.names = c(NA,
-2L))

answered Jan 02 '21 at 23:31

ThomasIsCoding

96,636
9
24
81

Thanks, I forgot to include something. – v_head Jan 03 '21 at 11:06

score 2 · Accepted Answer · answered Jan 03 '21 at 02:35

2

You can use vector recycling method to create two column dataframe.

result <- data.frame(newcol1 = unlist(df[c(TRUE, FALSE)]), 
                     newcol2 = unlist(df[c(FALSE, TRUE)]), row.names = NULL)

result

#  newcol1 newcol2
#1       a       b
#2       f       g
#3       c       d
#4       h       i

data

df <- structure(list(col1 = c("a", "f"), col2 = c("b", "g"), col3 = c("c", 
"h"), col4 = c("d", "i")), class = "data.frame", row.names = c(NA, -2L))

answered Jan 03 '21 at 02:35

Ronak Shah

377,200
20
156
213

Thanks, I forgot to include something. – v_head Jan 03 '21 at 11:06
@stackovf1 You can include the columns that you want `df <- df[1:4]` and then use the above answer. – Ronak Shah Jan 03 '21 at 11:23
thanks, I have another question https://stackoverflow.com/questions/65549351/rbinding-two-data-frame-with-same-num-of-columns – v_head Jan 03 '21 at 11:36

score 1 · Answer 3 · answered Jan 02 '21 at 23:26

1

Create example:

dd <- as.data.frame(matrix(letters[1:8], byrow=TRUE, nrow=2))

ss <- function(x) {
    ## remove data-frame structure, convert to 2x2 matrix
    m <- matrix(unlist(x),byrow=TRUE,2)
    ## set new names
    names(m) <- c("newcol1","newcol2")
    return(m)
}

Apply the function to each row and rbind() together:

rbind(ss(dd[1,]), ss(dd[2,]))

answered Jan 02 '21 at 23:26

Ben Bolker

211,554
25
370
453

Thanks, I forgot to include something. – v_head Jan 03 '21 at 11:06

rbinding two columns together in a dataframe

3 Answers3