R - Filter data to only include date X and following date-CodePudding

I have data structured like below, but with many more columns.

I need to filter the data to include only instances where a person has a date of X and X 1.

In this example only person B and C should remain, and only the rows with directly adjacent dates. So rows 2,3,5,6 should be the only remaining ones.

Once it is filtered I need to count how many times this occurred as well as do calculations on the other values, likely summing up the Values column for the X 1 date.

Person <- c("A","B","B","B","C","C","D","D")
Date <- c("2021-01-01","2021-01-01","2021-01-02","2021-01-04","2021-01-09","2021-01-10","2021-01-26","2021-01-29")
Values <- c(10,15,6,48,71,3,1,3)

df <- data.frame(Person, Date, Values)
df

How would I accomplish this?

CodePudding user response：

end_points <- df %>%
  mutate(Date = as.Date(Date)) %>%
  group_by(Person) %>%
  filter(Date -  lag(Date) == 1 | lead(Date) - Date == 1) %>%
  ungroup()

Result

end_points
# A tibble: 4 x 3
  Person Date       Values
  <chr>  <date>      <dbl>
1 B      2021-01-01     15
2 B      2021-01-02      6
3 C      2021-01-09     71
4 C      2021-01-10      3

2nd part:

end_points %>%
  group_by(Person) %>%
  slice_max(Date) %>%
  ungroup() %>%
  summarize(total = sum(Values))