问题
I have a column of strings in my data set formatted as year week (e.g. '201401' is equivalent to 7th April 2014, or the first fiscal week of the year)
I am trying to convert these to a proper date so I can manipulate them later, however I always receive the dame date for a given year, specifically the 14th of April.
e.g.
test_set <- c('201401', '201402', '201403')
as.Date(test_set, '%Y%U')
gives me:
[1] "2014-04-14" "2014-04-14" "2014-04-14"
回答1:
Try something like this:
> test_set <- c('201401', '201402', '201403')
>
> extractDate <- function(dateString, fiscalStart = as.Date("2014-04-01")) {
+ week <- substr(dateString, 5, 6)
+ currentDate <- fiscalStart + 7 * as.numeric(week) - 1
+ currentDate
+ }
>
> extractDate(test_set)
[1] "2014-04-07" "2014-04-14" "2014-04-21"
Basically, I'm extracting the weeks from the start of the year, converting it to days and then adding that number of days to the start of the fiscal year (less 1 day to make things line up).
回答2:
Not 100% sure what is your desired output but this may work
as.Date(paste0(substr(test_set, 1, 4), "-04-07")) +
(as.numeric(substr(test_set, 5, 6)) - 1) * 7
# [1] "2014-04-07" "2014-04-14" "2014-04-21"
来源:https://stackoverflow.com/questions/29631363/convert-year-week-string-to-date