Extract values based on conidtion of another column

Question

case_number <- c(\"1\", \"1\", \"2\", \"2\", \"2\", \"3\", \"3\") 
type <- c(\"STD\", \"STD2\", \"STD\", \"STD3\", \"STD2\", \"STD\", \"STD2\") 
date <- as.Date         


        

Answer 1

Here's a shot:

myfilter <- function(x) {
  r <- rle(x %in% c("STD", "STD2"))
  any(r$lengths[r$values] > 1)
}

library(dplyr)
data %>%
  group_by(case_number) %>%
  filter(myfilter(type)) %>%
  ungroup()
# # A tibble: 4 x 3
#   case_number type  date      
#               
# 1 1           STD   2008-11-01
# 2 1           STD2  2009-03-25
# 3 3           STD   2015-03-14
# 4 3           STD2  2015-04-15

It does not care about order, just about finding either of them in a chain of two (or more).