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rdplyrtibble

Seeking help in mutate in tibble

I have inventory of an item at the start of each day stored in tibble with column name - morning. I want to create another column (evening) which will have inventory at the end of the day (same as the inventory in next morning).

Can someone please correct my code below -

library(dplyr)

tbl <- tibble(morning = 5:10:95)

tbl <- tbl %>%
mutate(evening = c(morning[2, nrow(tbl)], NULL))
Solution

  • Use the function lead:

    tbl %>%
  mutate(evening = lead(morning))
# A tibble: 6 x 2
  morning evening
    <int>   <int>
1       5       6
2       6       7
3       7       8
4       8       9
5       9      10
6      10      NA

    Test data:

    tbl <- tibble(morning = 5:10)