Store Time in R

Description

Store Time in R

Usage

pl$PTime(x, tu = c("s", "ms", "us", "ns"), format = "%H:%M:%S")

Arguments

`x`	an integer or double vector of n epochs since midnight OR a char vector of char times passed to as.POSIXct converted to seconds.
`tu`	timeunit either "s","ms","us","ns"
`format`	a format string passed to as.POSIXct format via …

Details

PTime should probably be replaced with package nanotime or similar.

base R is missing encoding of Time since midnight "s" "ms", "us" and "ns". The latter "ns" is the standard for the polars Time type.

Use PTime to convert R doubles and integers and use as input to polars functions which needs a time.

Loosely inspired by data.table::ITime which is i32 only. PTime must support polars native timeunit is nanoseconds. The R double(float64) can imitate a i64 ns with full precision within the full range of 24 hours.

PTime does not have a time zone and always prints the time as is no matter local machine time zone.

An essential difference between R and polars is R prints POSIXct/lt without a timezone in local time. Polars prints Datetime without a timezone label as is (GMT). For POSIXct/lt taged with a timexone(tzone) and Datetime with a timezone(tz) the behavior is the same conversion is intuitive.

It appears behavior of R timezones is subject to change a bit in R 4.3.0, see polars unit test test-expr_datetime.R/"pl$date_range Date lazy/eager".

Value

a PTime vector either double or integer, with class "PTime" and attribute "tu" being either "s","ms","us" or "ns"

Examples

library("polars")


# make PTime in all time units
pl$PTime(runif(5) * 3600 * 24 * 1E0, tu = "s")

#> PTime [ double ]: number of epochs [ s ] since midnight
#> [1] "12:25:04 val: 44704" "21:01:30 val: 75690" "14:29:26 val: 52166"
#> [4] "18:38:45 val: 67125" "18:46:44 val: 67604"

pl$PTime(runif(5) * 3600 * 24 * 1E3, tu = "ms")

#> PTime [ double ]: number of epochs [ ms ] since midnight
#> [1] "02:03:47:725ms val: 7427725"  "20:04:52:990ms val: 72292990"
#> [3] "23:08:10:379ms val: 83290379" "22:56:32:572ms val: 82592572"
#> [5] "00:07:09:576ms val: 429576"

pl$PTime(runif(5) * 3600 * 24 * 1E6, tu = "us")

#> PTime [ double ]: number of epochs [ us ] since midnight
#> [1] "22:08:33:388_028us val: 79713388028" "15:35:30:468_850us val: 56130468850"
#> [3] "19:10:03:740_807us val: 69003740807" "13:13:12:593_675us val: 47592593675"
#> [5] "11:34:20:555_201us val: 41660555201"

pl$PTime(runif(5) * 3600 * 24 * 1E9, tu = "ns")

#> PTime [ double ]: number of epochs [ ns ] since midnight
#> [1] "12:30:44:973_537_325ns val: 45044973537325"
#> [2] "04:23:48:095_579_892ns val: 15828095579892"
#> [3] "15:11:24:830_906_242ns val: 54684830906242"
#> [4] "23:41:11:392_180_770ns val: 85271392180770"
#> [5] "13:11:07:682_162_672ns val: 47467682162672"

pl$PTime("23:59:59")

#> PTime [ double ]: number of epochs [ s ] since midnight
#> [1] "23:59:59 val: 86399"

as_polars_series(pl$PTime(runif(5) * 3600 * 24 * 1E0, tu = "s"))

#> polars Series: shape: (5,)
#> Series: '' [time]
#> [
#>  02:49:20
#>  23:37:36
#>  12:06:32
#>  04:35:07
#>  06:15:59
#> ]

pl$lit(pl$PTime("23:59:59"))$to_series()

#> polars Series: shape: (1,)
#> Series: '' [time]
#> [
#>  23:59:59
#> ]

pl$lit(pl$PTime("23:59:59"))$to_r()

#> PTime [ double ]: number of epochs [ ns ] since midnight
#> [1] "23:59:59:000_000_000ns val: 8.6399e+13"