How do I create a column called "northsouth" that tells me if an ID visits latitudes that are both above and below 35.
df_input <- data.frame (ID = c(12, 12, 12, 12, 13, 13), lat = c(32, 34, 40, 39, 32, 30))
df_result <- data.frame (portID = c(12, 13), northsouth = c("yes", "no"))
You could do
library(tidyverse)
df_input %>%
group_by(ID) %>%
summarize(northsouth = max(lat) > 35 & min(lat) < 35)
#> # A tibble: 2 x 2
#> ID northsouth
#> <dbl> <lgl>
#> 1 12 TRUE
#> 2 13 FALSE
Created on 2022-07-24 by the reprex package (v2.0.1)