tind (version 0.2.4)

calendrical-computations: Calendrical Computations in tind Package

Description

The following functions can be used for calendrical computations, especially determining dates of movable observances. All function are vectorised.

nth_day_of_year returns the date of the nth day of a year.

last_day_in_month and last_day_in_quarter return the date of the last day in a month or a quarter.

nth_dw_in_month returns the date of the nth day of week in a month.

last_dw_in_month returns the date of the last day of week in a month.

nth_dw_after and nth_dw_before calculate the nth occurrence of a day of week after or before given date.

easter returns the date of Easter in a year.

Usage

nth_day_of_year(nth, y)
last_day_in_month(m)
last_day_in_quarter(q)
nth_dw_in_month(nth, dw, m)
last_dw_in_month(dw, m)
nth_dw_after(nth, dw, d)
nth_dw_before(nth, dw, d)
easter(y)

Value

An object of tind class with dates (type "d").

Arguments

nth

a numeric value or vector of indices (1--366 for nth_day_of_year, 1--5 for nth_dw_in_month). A positive integer (vector) for nth_dw_after and nth_dw_before.

y, q, m, d

an object of tind class or an R object coercible to it.

dw

a numeric value or vector of days of week (values in range 1--7 with Monday as the 1st day).

See Also

time-index-components, time-index-properties, Ops. Further examples of application of these functions can be found in calendar documentation. For calendrical computations involving business days see bizday.

Examples

# Thanksgiving in the US is observed on the fourth Thursday of November,
# which in 2019 was on:
nth_dw_in_month(4, 4, 201911)
# and Black Friday?
nth_dw_in_month(4, 4, 201911) + 1

# Daylight Saving Time in the EU in 2019 began on the last Sunday in March,
# which was on:
last_dw_in_month(7, 201903)

# International Monetary Market dates in 2022 - 3rd Wednesday
# of March, June, September, and December
nth_dw_in_month(3, 3, tind(y = 2022, m = 3 * 1:4))

# determine frequencies of Easter months over the last 100 years
# Easter months
em <- month(easter(as.year(today()) + (-99:0)), labels = TRUE)
# table and barplot
table(em) / length(em) * 100
if (require("graphics", quietly = TRUE)) {
    barplot(table(em) / length(em) * 100, ylim = c(0, 100), col = "#faf06d")
}