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This is a year-month-day method for the calendar_start() and calendar_end() generics. They adjust components of a calendar to the start or end of a specified precision.


# S3 method for clock_year_month_day
calendar_start(x, precision)

# S3 method for clock_year_month_day
calendar_end(x, precision)




A year-month-day vector.



One of:

  • "year"

  • "month"

  • "day"

  • "hour"

  • "minute"

  • "second"

  • "millisecond"

  • "microsecond"

  • "nanosecond"


x at the same precision, but with some components altered to be at the boundary value.


# Hour precision
x <- year_month_day(2019, 2:4, 5, 6)
#> <year_month_day<hour>[3]>
#> [1] "2019-02-05T06" "2019-03-05T06" "2019-04-05T06"

# Compute the start of the month
calendar_start(x, "month")
#> <year_month_day<hour>[3]>
#> [1] "2019-02-01T00" "2019-03-01T00" "2019-04-01T00"

# Or the end of the month, notice that the hour value is adjusted as well
calendar_end(x, "month")
#> <year_month_day<hour>[3]>
#> [1] "2019-02-28T23" "2019-03-31T23" "2019-04-30T23"

# Compare that with just setting the day of the month to `"last"`, which
# doesn't adjust any other components
set_day(x, "last")
#> <year_month_day<hour>[3]>
#> [1] "2019-02-28T06" "2019-03-31T06" "2019-04-30T06"

# You can't compute the start / end at a more precise precision than
# the input is at
try(calendar_start(x, "second"))
#> Error in calendar_start_end_checks(x, x_precision, precision, "start") : 
#>   Can't compute the start of `x` ("hour") at a more precise
#> precision ("second").