library(tidyverse)
library(lubridate)
(mydf <- structure(
list(
date = structure(c(7305, 7306, 7307, 7308, 7309), class = "Date"),
val = c(0.01, 0.01, 0.01, 0.01, 0.01)
),
row.names = c(NA, -5L),
class = c("tbl_df", "tbl", "data.frame")
))
mydf %>% group_by(wk_of_date=week(date)) %>% summarise(sumval=sum(val))