strsplit by row and distribute results by column in data.frame

Question

So I have the data.frame

dat = data.frame(x = c(\'Sir Lancelot the Brave\', \'King Arthur\',  
                       \'The Black Knight\', \'The Rabbit\'), stri         


        

Answer 1

This is an old question, I know, but I thought I would share two additional options.

Option 1

concat.split from my "splitstackshape" package was designed exactly for this type of thing.

library(splitstackshape)
concat.split(dat, "x", " ")
#                        x  x_1      x_2    x_3   x_4
# 1 Sir Lancelot the Brave  Sir Lancelot    the Brave
# 2            King Arthur King   Arthur             
# 3       The Black Knight  The    Black Knight      
# 4             The Rabbit  The   Rabbit        

---

Option 2

data.table has recently (as of version 1.8.11, I believe) had some additions to its arsenal, notably in this case dcast.data.table. To use it, unlist the split data (as was done in @mnel's answer), create a "time" variable using .N (how many new values per row), and use dcast.data.table to transform the data into the form you are looking for.

library(data.table)
library(reshape2)
packageVersion("data.table")
# [1] ‘1.8.11’

DT <- data.table(dat)
S1 <- DT[, list(X = unlist(strsplit(x, " "))), by = seq_len(nrow(DT))]
S1[, Time := sequence(.N), by = seq_len]
dcast.data.table(S1, seq_len ~ Time, value.var="X")
#    seq_len    1        2      3     4
# 1:       1  Sir Lancelot    the Brave
# 2:       2 King   Arthur     NA    NA
# 3:       3  The    Black Knight    NA
# 4:       4  The   Rabbit     NA    NA