The goal of warp is to provide tooling to group dates by a variety of periods, such as: yearly, monthly, by second, by week of the month, and more.

You can install the release version from CRAN with:

You can install the development version from GitHub with:

One of the core functions in warp is `warp_distance()`

, which allows you to provide a date time vector and compute the “distance” from an `origin`

. For example, this computes the number of months from the unix epoch.

```
x <- as.Date("1970-01-01") + -2:2
x
#> [1] "1969-12-30" "1969-12-31" "1970-01-01" "1970-01-02" "1970-01-03"
warp_distance(x, period = "month")
#> [1] -1 -1 0 0 0
```

The values that `warp_distance()`

returns correspond to the distance from `x`

to the `origin`

, in units defined by the `period`

and the width defined by `every`

. The `origin`

defaults to the unix epoch of `1970-01-01 00:00:00`

in the time zone of `x`

, but you can change that. In this case the distances are saying that, for example, `"1970-01-02"`

is in the same month as the origin, and `"1969-12-31"`

is 1 month group away.

You can also compute daily distances. Rather than grouping by 1 day, let’s lump every 2 days together, starting from the default `origin`

.

```
# Groups 1970-01-01 and 1970-01-02 together
warp_distance(x, period = "day", every = 2)
#> [1] -1 -1 0 0 1
```

You will often want to set your own `origin`

date. Let’s shift it forward 1 to `1970-01-02`

.

```
origin <- as.Date("1970-01-02")
origin
#> [1] "1970-01-02"
# Groups 1970-01-02 and 1970-01-03 together
warp_distance(x, period = "day", every = 2, origin = origin)
#> [1] -2 -1 -1 0 0
```

Another interesting period to group by is the `"mweek"`

, i.e. the week of the month. Notice that days 1-7 of January 1970 are grouped into the same bucket. Also note that days 29-31 of December 1969 fell at the end of their corresponding month. This irregular week of size 3 is treated as the 5th week of that month, but the offset value of `-1`

is still the number of week buckets from the `origin`

of `1970-01-01`

.

```
y <- as.Date("1969-12-28") + 0:14
tibble::tibble(
y = y,
mweek = warp_distance(y, "mweek")
)
#> # A tibble: 15 x 2
#> y mweek
#> <date> <dbl>
#> 1 1969-12-28 -2
#> 2 1969-12-29 -1
#> 3 1969-12-30 -1
#> 4 1969-12-31 -1
#> 5 1970-01-01 0
#> 6 1970-01-02 0
#> 7 1970-01-03 0
#> 8 1970-01-04 0
#> 9 1970-01-05 0
#> 10 1970-01-06 0
#> 11 1970-01-07 0
#> 12 1970-01-08 1
#> 13 1970-01-09 1
#> 14 1970-01-10 1
#> 15 1970-01-11 1
```

The algorithm for `warp_distance()`

was inspired by `xts::endpoints()`

.