nanotime: Nanosecond resolution datetime functionality

In eddelbuettel/nanotime: Nanosecond-Resolution Time Support for R

Nanosecond resolution datetime functionality

Description

Functions to operate on nanosecond time resolution using integer64 bit representation. Conversion functions for several standard R types are provided, and more will be added as needed.

Usage

nanotime(from, ...)

as.nanotime(from, ...)

## S4 method for signature 'character'
nanotime(from, format = "", tz = "")

## S4 method for signature 'character'
as.nanotime(from, format = "", tz = "")

nanotime.matrix(x)

## S4 method for signature 'POSIXct'
nanotime(from, accurate = TRUE)

## S4 method for signature 'POSIXct'
as.nanotime(from, accurate = TRUE)

## S4 method for signature 'POSIXlt'
nanotime(from)

## S4 method for signature 'POSIXlt'
as.nanotime(from)

## S4 method for signature 'Date'
nanotime(from)

## S4 method for signature 'Date'
as.nanotime(from)

## S4 method for signature 'nanotime'
print(x, format = "", tz = "", quote = FALSE, ...)

## S4 method for signature 'nanotime'
show(object)

## S3 method for class 'nanotime'
format(x, format = "", tz = "", ...)

## S3 method for class 'nanotime'
index2char(x, ...)

## S3 method for class 'nanotime'
as.POSIXct(x, tz = "", ...)

## S3 method for class 'nanotime'
as.POSIXlt(x, tz = "", ...)

## S3 method for class 'nanotime'
as.Date(x, ...)

## S3 method for class 'nanotime'
as.data.frame(x, ...)

## S3 method for class 'nanotime'
as.integer64(x, ...)

## S4 method for signature 'nanotime,character'
e1 - e2

## S4 method for signature 'nanotime,nanotime'
e1 - e2

## S4 method for signature 'nanotime,integer64'
e1 - e2

## S4 method for signature 'nanotime,numeric'
e1 - e2

## S4 method for signature 'ANY,nanotime'
e1 - e2

## S4 method for signature 'nanotime,ANY'
e1 - e2

## S4 method for signature 'nanotime,ANY'
e1 + e2

## S4 method for signature 'nanotime,integer64'
e1 + e2

## S4 method for signature 'nanotime,numeric'
e1 + e2

## S4 method for signature 'ANY,nanotime'
e1 + e2

## S4 method for signature 'integer64,nanotime'
e1 + e2

## S4 method for signature 'numeric,nanotime'
e1 + e2

## S4 method for signature 'nanotime,nanotime'
e1 + e2

## S4 method for signature 'nanotime,nanotime'
Arith(e1, e2)

## S4 method for signature 'nanotime,ANY'
Arith(e1, e2)

## S4 method for signature 'ANY,nanotime'
Arith(e1, e2)

## S4 method for signature 'nanotime,character'
Compare(e1, e2)

## S4 method for signature 'character,nanotime'
Compare(e1, e2)

## S4 method for signature 'nanotime,POSIXt'
Compare(e1, e2)

## S4 method for signature 'POSIXt,nanotime'
Compare(e1, e2)

## S4 method for signature 'nanotime,ANY'
Compare(e1, e2)

## S4 method for signature 'nanotime,ANY'
Logic(e1, e2)

## S4 method for signature 'ANY,nanotime'
Logic(e1, e2)

## S4 method for signature 'nanotime'
Math(x)

## S4 method for signature 'nanotime'
Math2(x, digits)

## S4 method for signature 'nanotime'
Summary(x, ..., na.rm = FALSE)

## S4 method for signature 'nanotime'
min(x, ..., na.rm = FALSE)

## S4 method for signature 'nanotime'
max(x, ..., na.rm = FALSE)

## S4 method for signature 'nanotime'
range(x, ..., na.rm = FALSE)

## S4 method for signature 'nanotime'
Complex(z)

## S4 method for signature 'nanotime'
x[[i, j, ..., drop = FALSE]]

## S4 method for signature 'nanotime,numeric'
x[i, j, ..., drop = FALSE]

## S4 method for signature 'nanotime,logical'
x[i, j, ..., drop = FALSE]

## S4 method for signature 'nanotime,character'
x[i, j, ..., drop = FALSE]

## S4 method for signature 'nanotime,ANY'
x[i, j, ..., drop = FALSE]

## S4 replacement method for signature 'nanotime,ANY,ANY,ANY'
x[i, j, ...] <- value

## S3 method for class 'nanotime'
c(...)

## S4 replacement method for signature 'nanotime'
names(x) <- value

## S4 method for signature 'nanotime'
is.na(x)

NA_nanotime_

## S3 method for class 'nanotime'
as.character(x, ...)

## S3 method for class 'nanoduration'
as.data.frame(x, ...)

Arguments

...	further arguments passed to or from methods.
format	A character string. Can also be set via options("nanotimeFormat") and uses ‘%Y-%m-%dT%H:%M:%E9S%Ez’ as a default and fallback
tz	character specifying a timezone which is required for as.POSIXct, as.POSIXlt and can be specified for as.nanotime, format and print; it can also be set via options("nanotimeTz") and uses ‘UTC’ as a default and fallback
x, from	nanotime objects
accurate	in the conversion from POSIXct to nanotime, indicates if one wants to preserve the maximum precision possible; the default is TRUE, but in most situations the loss of precision is negligible, and setting this parameter to TRUE will make the conversion nearly an order of magnitude faster
quote	indicates if the output of print should be quoted
object	argument for method show
e1	Operand of class nanotime
e2	Operand of class nanotime
digits	Required for Math2 signature but ignored here
na.rm	a logical indicating whether missing values should be removed.
z	Required for Complex signature but ignored here
i	index specifying elements to extract or replace.
j	Required for [ signature but ignored here
drop	Required for [ signature but ignored here
value	argument for nanotime-class

Format

An object of class nanotime of length 1.

Details

Notice that the conversion from POSIXct explicitly sets the last three digits to zero. Nanosecond time stored in a 64-bit integer has nineteen digits precision where doubles (which are used internally for POSIXct as well) only have sixteen digits. So rather than showing three more (essentially random) digits it is constructed such that these three additional digits are zeros.

Value

A nanotime object

Caveats

Working with dates and times is difficult. One needs a representation of both time points and time duration. In R, think of Date or POSIXct objects for the former, and difftime for the later. Here we have time points nanotime, an interval type nanoival and two flavors of duration which are a simple count of nanoseconds nanoduration and a calendar duration that is able to track concepts such as months and days nanoperiod. Point in time and intervals are all based on durations relative to the epoch of January 1, 1970.

Input and Output Format

Formatting and character conversion for nanotime objects is done by functions from the RcppCCTZ package relying on code from its embedded CCTZ library. The default format is ISO3339 compliant: %Y-%m-%dT%H:%M:%E9S%Ez. It specifies a standard ISO 8601 part for date and time — as well as nine digits of precision for fractional seconds (down to nanoseconds) and on offset (typically zero as we default to UTC). It can be overriden by using options() with the key of nanotimeFormat and a suitable value. Similarly, nanotimeTz can be used to select a different timezone.

For input, some slack it cut, and various shortened formats are accepted by default such as 2020-03-10 or 2020-03-10 18:16:00, or 2020-03-10 18:16:00.001 (and the ‘T’ separator is optional.

tz parameter usage in constructors

The tz parameter is allowed only when constructing a nanotime from a character. This is because any numeric, Date and POSIXct is de facto considered an offset since the epoch. On the contrary, a character is considered interpretable and hence if it does not contain a timezone in its representation, it is possible to specify the tz argument to specify in which timezone it should be interpreted. This is useful in particular if one wants to convert a Date to be aligned to the beginning of the day in a specific timezone; in this case one should convert the Date to a character before calling the nanotime constructor with the desired timezone.

Author(s)

Dirk Eddelbuettel

Leonardo Silvestri

See Also

nanoival, nanoduration, nanoperiod, seq.nanotime as well as the documentation in package RcppCCTZ.

Examples

## Not run: 
x <- nanotime(1)
print(x)
as.nanotime("1970-01-01T00:00:00.000000001+00:00")
as.nanotime("2020-03-10 Europe/Berlin")
as.nanotime("2020-03-10 18:31:23.001", tz="America/New_York")
as.nanotime("2020-03-10T040947190301440", format="%Y-%m-%dT%H%M%S%E*f")
x <- x + 1
print(x)
format(x)
x <- x + 10
print(x)
format(x)
nanotime(Sys.time()) + 1:3  # three elements each 1 ns apart
seq(x, by=as.nanoperiod("1d"), length.out=5, tz="Asia/Tokyo")

## End(Not run)

eddelbuettel/nanotime documentation built on Feb. 21, 2024, 11:40 p.m.