Group Data in R for consecutive rows

Question

If there\'s not a quick 1-3 liner for this in R, I\'ll definitely just use linux sort and a short python program using groupby, so don\'t bend over

Answer 1

with(df_in, {
  aggregate(day, list('ID'=ID, 'weight'=weight), 
            function(x) c('min_day' = min(x), 'max_day' = max(x)))
})

Produces:

  ID weight x.min_day x.max_day
1  1    150         1         5
2  1    151         3         3
3  2    170         1         3
4  2    171         4         5