Split string by final space in R

Question

I have a vector a strings with a number of spaces in. I would like to split this into two vectors split by the final space. For example:

vec <- c('This is one', 'And another', 'And one more again')

Should become

vec1 = c('This is', 'And', 'And one more again')
vec2 = c('one', 'another', 'again')

Is there a quick and easy way to do this? I have done similar things before using gsub and regex, and have managed to get the second vector using the following

vec2 <- gsub(".* ", "", vec)

But can't work out how to get vec1.

Thanks in advance

Answer 1

Here is one way using a lookahead assertion:

do.call(rbind, strsplit(vec, ' (?=[^ ]+$)', perl=TRUE))
#      [,1]           [,2]     
# [1,] "This is"      "one"    
# [2,] "And"          "another"
# [3,] "And one more" "again"