Grouped Sequences in dplyr | Alan Yeung

[utterances-bot]

Grouped Sequences in dplyr | Alan Yeung

For a piece of work I had to calculate the number of matches that a team plays away from home in a row, which we will call days_on_the_road. I was not sure how to do this with dplyr but it’s basically a ‘grouped sequence’. For this post, I’ve created some dummy data to illustrate this idea. The num_matches_away variable is what we want to mimic using some data manipulation.

https://alan-y.netlify.com/post/2023-11-05-grouped-sequences-in-dplyr/

[havukkala]

Hi Alan
I got this short solution:
sports_df2 %>%
group_by(team) %>%

cumulated counts of runs of A and H

mutate(RLE = sequence( rle(home_or_away)$lengths) ) %>%

make H numbers zero

mutate(RLE = ifelse(home_or_away == "A", RLE, 0) ) %>%
ungroup()

Hope this helps
Ilkka Havukkala

[alan-y]

Thanks @havukkala, that's a really neat solution!