R split string at last whitespace chars using tidyr::separate

Question

Suppose I have a dataframe like this:

df<-data.frame(a=c(\"AA\",\"BB\"),b=c(\"short string\",\"this is the longer string\"))

I would like to

Answer 1

We can use extract from tidyr by using the capture groups ((...)). We match zero or more characters (.*) and place it within the parentheses ((.*)), followed by zero or more space (\\s+), followed by the next capture group which includes only characters that are not a space ([^ ]) until the end ($) of the string.

library(tidyr)
extract(df, b, into = c('partA', 'partB'), '(.*)\\s+([^ ]+)$')
#   a              partA  partB
#1 AA              short string
#2 BB this is the longer string