Change day of the month in a Date to first day (01)

Question

I want to set the day of month in a Date to start date of current month (01). Now I use the following:

currentDate <- Sys.Date()         


        

Answer 1

Yes, there is a one-liner for that using function cut:

cut(Sys.Date(), "month")
[1] 2012-11-01
Levels: 2012-11-01

Answer 2

as.Date(paste0(format(Sys.Date(), "%Y-%m"), "-01"))

Answer 3

lubridate's floor_date keeps it a Date

library(lubridate)

floor_date(Sys.Date(), "month")

Answer 4

Also one line using format function:

format(Sys.Date(),"01-%m-%Y")
[1] "01-06-2017"

Answer 5

Using lubridate (also work with sec, min, hour, mon, year etc.)

library(lubridate)

dt <- Sys.Date()
day(dt) <- 01

dt
# [1] "2018-01-01"