Search for multiple occurrences of substring within string

Question

Below is my dataset. I am using the function str_detect() on the key column like so:

str_detect(mydata$Key, 'R')

I want to be able to search for strings that contain 2 R's. Obviously in the below example I could just search for R002R009 but I do not always know the numbers attached to the R's so I just want to search for strings with 2 R's.

I need to be able to use it inside an ifelse statement

 mydata[1:3]
           IDENTIFIER  DATE_TIME         X-VALUE     Y-VALUE      Key
    1      214461707   1/04/2019 8:25           1         -3       A001
    2      214461789   1/04/2019 10:16          1         -2       R001
    3      214461789   1/04/2019 10:16          1         -5       R002R009

Answer 1

You can use str_count to count number of occurrences of a letter and use it in filter.

library(dplyr)
library(stringr)

mydata %>% filter(str_count(Key, 'R') == 2)

#   FACILITY_ID      DATE_TIME XVALUE YVALUE      Key
#3   214461789 1/04/201910:16      1     -5 R002R009