将月份的最后一天发送到 R 中的 function

Question

May be this isn't a nice way to do this but I have to run over every last day of month into a function for last 4 years and rbind the output of all the dates into one data.frame .

I already have my dataframe DF in my environment.

MY FUNCTION

Part 1 I need Dynamic Date Insertion here to loop over dates automatically.

myfunct <- function (date) {


abc <- subset(DF, HIRE_DATE <= date || LAST_WORKING_DATE <= date )
abc <- subset(abc, TDATE <= date)

augact <- abc %>% 
  group_by(ID_Merged) %>%
  slice(which.max(TDATE))


augact <- subset(augact, ASSIGNMENT_STATUS == "ACTIVE")

hc_cnt <- nrow(augact)
x <- data.frame(date, hc_cnt)

return(x)
}

Part 2

Row Binding the output into one.

x <- myfunct("2021-01-31")
y <- myfunct("2021-08-31")
dfmerged <- rbind(x,y)

Please remember I want to automatically send the last day of the every month. May be there's some package that can do this.

rbind output us as follow

        date hc_cnt
1 2021-01-31   2946
2 2021-08-31   3039

Answer 1

I meant this as a comment, but since it is really another answer, it should be visible...

To obtain a Date vector listing the last date of each month from Date start to Date end , using base R only, you can do:

last_of_month <- function(start, end) {
  ## Replace "YYYY-MM-DD" with "YYYY-MM-01"
  start <- as.Date(format(start, "%Y-%m-01"))
  seq(start, end + 1, by = "1 month")[-1L] - 1
}

last_of_month(as.Date("2020-01-15"), as.Date("2021-11-18"))
#  [1] "2020-01-31" "2020-02-29" "2020-03-31" "2020-04-30" "2020-05-31"
#  [6] "2020-06-30" "2020-07-31" "2020-08-31" "2020-09-30" "2020-10-31"
# [11] "2020-11-30" "2020-12-31" "2021-01-31" "2021-02-28" "2021-03-31"
# [16] "2021-04-30" "2021-05-31" "2021-06-30" "2021-07-31" "2021-08-31"
# [21] "2021-09-30" "2021-10-31"

Answer 2

May be I can help you. You can get list of all ends of months by hand:

library(data.table)

date_start <- as.Date("2020-01-01")
date_end <- Sys.Date()

all_dates <- .Date(date_start:date_end)
ends_of_months <- all_dates[which(month(all_dates) != month(lead(all_dates)))]