CODEWITHSUNDEEP
r
HoHoHo
HoHoHo

Reputation: 311

Create grouping variable based on names of data frame column

I have a DF with column of names

DF
a     b
a.b   1
a.c   2
a.d   3
b.c   4
b.l   5
b.d   6
c.a   6
c.b   7

I need to create new column which contains symbol before . in DF$a, so that

DF
    a     b   c
    a.b   1   a
    a.c   2   a
    a.d   3   a
    b.c   4   b
    b.l   5   b
    b.d   6   b
    c.a   6   c
    c.b   7   c

Is it possible? Thank you for any suggestions.

Upvotes: 0

Views: 45

Answers (1)

akrun
akrun

Reputation: 886938

We can use sub to match the dot character(\\.) followed by one or more characters to the end of the string and replace with ''.

DF$c <- sub("\\..*$", "", DF$a)
DF$c
#[1] "a" "a" "a" "b" "b" "b" "c" "c"

Or

library(stringr)
str_extract(DF$a, "\\w+")

Upvotes: 1

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