R: counting consecutive days

Question

I am having trouble solving this one, I have a DF with a list of count data. For example something like this:

 DATE        TIME     ID
 2014-02-14  15:02    1
 2         


        

Answer 1

We can use dplyr. First, convert your data in proper date format:

z$date <- as.Date(as.character(z$date), format = "%d-%m-%y")

Now the function:

library(dplyr)
runchecker <- function(data, days){
  data %>% arrange(date) %>%
           group_by(ID) %>%
           mutate(diff = c(0, diff(date)),
                  periodID = 1 + cumsum(diff > days)) %>%
           group_by(ID, periodID) %>%
           summarise(days = last(date) - first(date))
}

and call it on your data:

runchecker(data, 1)
Source: local data frame [4 x 3]
Groups: ID [?]

     ID periodID   days
  (int)    (dbl) (dfft)
1     1        1 0 days
2     2        1 3 days
3     3        1 0 days
4     4        1 0 days

NB your data has very few date changes or gaps, maybe include a better data set for testing?