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

Answer 1

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))))                                                                                                                          
} 

Answer 2

We can use a list instead of data.frame and convert it to a data.frame at the end. For instance:

df = list()
df2 = data.frame(col1 = 1:3, col2 = c('a','b','c'))
df = as.data.frame(cbind(df, as.matrix(df2)))
df

#   col1 col2
# 1    1    a
# 2    2    b
# 3    3    c

Answer 3

cbind.na from the qpcR package can do that.

    install.packages("qpcR")
    library(qpcR)
    qpcR:::cbind.na(1, 1:7)

Answer 4

Using rowr::cbind.fill

rowr::cbind.fill(df1,df2,fill = NA)
   A B
1  1 1
2  2 2
3  3 3
4  4 4
5  5 5
6 NA 6

Answer 5

When a and b are data frames, following should work just fine:

ab <- merge(a, b, by="row.names", all=TRUE)[,-1]

or another possibility:

rows <- unique(c(rownames(a), rownames(b)))
ab <- cbind(a[rows ,], b[rows ,])

Answer 6

I just find a trick that when we want to add columns into an empty dataframe, just rbind it at first time, than cbind it later.

    newdf <- data.frame()
    # add the first column
    newdf <- rbind(newdf,data.frame("col1"=c("row1"=1,"row2"=2)))
    # add the second column
    newdf <- cbind(newdf,data.frame("col2"=c("row1"=3,"row2"=4)))
    # add more columns
    newdf <- cbind(newdf,data.frame("col3"=c("row1"=5,"row2"=6)))
    # result
    #     col1 col2 col3
    #row1    1    3    5
    #row2    2    4    6

I don't know why, but it works for me.