How to create id variable by grouping sequenced numbers?

Question

I want to add ID variable in this data. If receipt_ids are sequenced numbers, then those have same IDs.

CUST_NO_ID  receipt_id      dollar
  12         29               


        

Answer 1

Had a similar notion to @Psidom, but he beat me to the punch with cumsum. Here's a dplyr solution. Adding in group_by can give you added flexibility if you want to restart ids by customer number.

df %>% 
  mutate(id = cumsum(c(TRUE, diff(receipt_id) != 1)))