R - dplyr 中字符串的列

Question

my dataframe look like this

x <-
  data.frame(
    id = c("123_1", "987_123")
  )

I'd like to create this result dataframe via dplyr mutate function. I just want to take first part before underscore sign and another one right after underscore sign.

result <-
  data.frame(
    id = c("123_1", "987_123"),
    af = c("123", "987"),
    ad = c("1", "123")
  )

Answer 1

1) tidyverse Use separate like this:

library(dplyr)
library(tidyr)

x %>%
  separate(id, c("af", "ad"), remove = FALSE)
##        id  af  ad
## 1   123_1 123   1
## 2 987_123 987 123

2) Base R

2a) read.table Without any packages use read.table

cbind(x, read.table(text = x$id, sep = "_", col.names = c("af", "ad"),
  colClasses = "character"))
##        id  af  ad
## 1   123_1 123   1
## 2 987_123 987 123

2b) sub or use sub :

transform(x, af = sub("_.*", "", id), ad = sub(".*_", "", id))
##        id  af  ad
## 1   123_1 123   1
## 2 987_123 987 123