CODEWITHSUNDEEP
r
rt.l
rt.l

Reputation: 306

Count events that occurred in sequence

In my setup, every month a city might observe the occurrence of an event or not. I want to count how many of these events have occurred in a row (in sequence) within each city.

I managed to implement a script with 2 for loops one inside each other, but I have over 1500 cities and around 250 months, so it took forever for the loops to conclude. Therefore, I'm looking for some faster and more elegant solution.


df <- data.frame(city = c(rep("a",10),rep("b",10)), month = c(1:10,1:10), event = c(0,0,0,1,0,1,1,1,0,1,1,1,0,0,0,1,1,1,1,0),                 desirable_output= c(0,0,0,1,0,1,2,3,0,1,1,2,0,0,0,1,2,3,4,0))

In this toy example, the column "desirable_output" shows my expected output.

Thanks in advance for any ideas.

Upvotes: 0

Views: 65

Answers (1)

arg0naut91
arg0naut91

Reputation: 14764

Try:

library(data.table)

setDT(df)[, desirable_output := cumsum(event), by = .(city, rleid(city, event))]

Upvotes: 1

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