This is a year-week-day method for the `calendar_group()`

generic.

Grouping for a year-week-day object can be done at any precision, as
long as `x`

is at least as precise as `precision`

.

## Usage

```
# S3 method for clock_year_week_day
calendar_group(x, precision, ..., n = 1L)
```

## Arguments

- x
`[clock_year_week_day]`

A year-week-day vector.

- precision
`[character(1)]`

One of:

`"year"`

`"week"`

`"day"`

`"hour"`

`"minute"`

`"second"`

`"millisecond"`

`"microsecond"`

`"nanosecond"`

- ...
These dots are for future extensions and must be empty.

- n
`[positive integer(1)]`

A single positive integer specifying a multiple of

`precision`

to use.

## Examples

```
x <- year_week_day(2019, 1:52)
# Group by 3 weeks
calendar_group(x, "week", n = 3)
#> <year_week_day<Sunday><week>[52]>
#> [1] "2019-W01" "2019-W01" "2019-W01" "2019-W04" "2019-W04" "2019-W04"
#> [7] "2019-W07" "2019-W07" "2019-W07" "2019-W10" "2019-W10" "2019-W10"
#> [13] "2019-W13" "2019-W13" "2019-W13" "2019-W16" "2019-W16" "2019-W16"
#> [19] "2019-W19" "2019-W19" "2019-W19" "2019-W22" "2019-W22" "2019-W22"
#> [25] "2019-W25" "2019-W25" "2019-W25" "2019-W28" "2019-W28" "2019-W28"
#> [31] "2019-W31" "2019-W31" "2019-W31" "2019-W34" "2019-W34" "2019-W34"
#> [37] "2019-W37" "2019-W37" "2019-W37" "2019-W40" "2019-W40" "2019-W40"
#> [43] "2019-W43" "2019-W43" "2019-W43" "2019-W46" "2019-W46" "2019-W46"
#> [49] "2019-W49" "2019-W49" "2019-W49" "2019-W52"
y <- year_week_day(2000:2020, 1, 1)
# Group by 2 years
calendar_group(y, "year", n = 2)
#> <year_week_day<Sunday><year>[21]>
#> [1] "2000" "2000" "2002" "2002" "2004" "2004" "2006" "2006" "2008" "2008"
#> [11] "2010" "2010" "2012" "2012" "2014" "2014" "2016" "2016" "2018" "2018"
#> [21] "2020"
```