seq.jdate: Generate regular sequences of Jalali dates

In shide: Date/Time Classes Based on Jalali Calendar

Generate regular sequences of Jalali dates

Description

The method for seq for objects of class jdate.

Usage

## S3 method for class 'jdate'
seq(from, to, by, length.out = NULL, along.with = NULL, ...)

Arguments

from	starting date. Required.
to	end date. Optional.
by	increment of the sequence. Optional. See ‘Details’.
length.out	integer, optional. Desired length of the sequence.
along.with	take the length from the length of this argument.
...	arguments passed to or from other methods.

Details

by can be specified in several ways:

• A number, taken to be in days.

• A object of class difftime.

• A character string, containing one of "day", "week", "month", "quarter" or "year". This can optionally be preceded by a (positive or negative) integer and a space, or followed by "s".

Value

A vector of jdate objects.

Comparison with seq.Date()

The source code of seq.jdate() is a modified version of the code used in base::seq.Date(). But a few behaviors of the latter are changed:

• In base R, invalid dates resolve by overflowing according to the number of days that the date is invalid by. But seq.jdate() resolves invalid dates by rolling forward to the first day of the next month.

• If usage of to and length.out results in a fractional sequence between from and to, base R keeps the fraction in the underlying data of the output Date object. But since jdate is built upon whole numbers, the fractional part is dropped in the output.

These differences are illustrated in the examples.

See Also

base::seq.Date()

Examples

# by days
seq(jdate("1402-01-01"), jdate("1402-01-10"), 1)
# by 2 weeks
seq(jdate("1402-01-01"), jdate("1402-04-01"), "2 weeks")
# first days of years
seq(jdate("1390-01-01"), jdate("1399-01-01"), "years")
# by month
seq(jdate("1400-01-01"), by = "month", length.out = 12)
# quarters
seq(jdate("1400-01-01"), jdate("1403-01-01"), by = "quarter")

# fractional dates are allowed in `seq.Date()`, but not in `seq.jdate()`
unclass(seq(as.Date(0), as.Date(3), length.out = 3))
unclass(seq(jdate(0), jdate(2), length.out = 3))

# resloving strategy for invalid dates is different in 'seq.jdate()' compared to 'seq.Date()'
seq(as.Date("2021-01-31"), by = "months", length.out = 2)
seq(jdate("1402-06-31"), by = "6 months", length.out = 2)

shide documentation built on Sept. 11, 2024, 6:37 p.m.