If Column Contains String then enter value for that row

Question

I have a dataframe that looks like this:

A     B
ABC1  0
DEF2  4
DEG0  4

How do I transform this so that if a row contains the letter "D" then insert the value "yes" in a new column and "no" if not.

Final dataframe should look like this:

A     B    C
ABC1  0    no
DEF2  4    yes
DEG0  4    yes

Try `ifelse(grepl("D", df$A), "yes", "no")` – akrun Oct 06 '16 at 18:37 — akrun, Oct 06 '16 at 18:37
good succinct question. Should not have been downvoted – Jake Jun 27 '17 at 17:53 — Jake, Jun 27 '17 at 17:53

score 31 · Accepted Answer · answered Oct 06 '16 at 19:02

31

We can use grepl to return a logical index by matching the 'D' in the 'A' column, and then with ifelse, change the logical vector to 'yes' and 'no'

df$C <- ifelse(grepl("D", df$A), "yes", "no")

answered Oct 06 '16 at 19:02

akrun

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is there dplyr way to achieve the same with mutate ? – user5249203 May 27 '22 at 13:13
1

@user5249203 it would be `library(dplyr);library(stringr);df % mutate(C = case_when(str_detect(A, "D") ~ "yes", TRUE ~ "no"))` – akrun May 27 '22 at 15:15

If Column Contains String then enter value for that row

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