Calculate days since last event in R

Question

My question involves how to calculate the number of days since an event last that occurred in R. Below is a minimal example of the data:

df <- data.frame         


        

Answer 1

I'm way late to the party, but I used tidyr::fill to make this easier. You essentially convert your non-events to missing values, then use fill to fill the NAs in with the last event, then subtract the current date from the last event.

I've tested this with a integer date column, so it might need some tweaking for a Date-type date column (especially the use of NA_integer_. I'm not sure what the underlying type is for Date objects; I'm guessing NA_real_.)

df %>%
  mutate(
    event = as.logical(event),
    last_event = if_else(event, true = date, false = NA_integer_)) %>%
  fill(last_event) %>%
  mutate(event_age = date - last_event)