tind Classtind class is designed to represent time indices of
different types and perform computations with them. Indices are
represented as vectors of integers or doubles. The following types of
time indices are supported:
Time indices can be constructed via calls to tind
constructor, using as.tind methods, or by calling
parse_t and strptind functions for parsing
arbitrary time index formats.
Before proceeding, let us load the package.
library("tind")The internal code for years is y.
The simplest way to construct year indices is to invoke
tind constructor with a single argument y.
(ys <- tind(y = 2010:2020))## year [tind]
## [1] 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020In as.tind method, integers in range 1800–2199 are
automatically interpreted as years. For instance:
(ys <- as.tind(2010:2020))## year [tind]
## [1] 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020To let as.tind know that numbers outside 1800–2199 range
should be interpreted as years, type argument has to be
provided as in:
(ys <- as.tind(c(1700, 1800, 1900, 2000, 2100), type = "y"))## year [tind]
## [1] 1700 1800 1900 2000 2100Convenience function as.year is a shortcut for
as.tind(*, type = "y"):
(ys <- as.year(c(1700, 1800, 1900, 2000, 2100)))## year [tind]
## [1] 1700 1800 1900 2000 2100Four-digit character strings in the format YYYY are also
automatically interpreted as year indices:
(ys <- as.tind(c("1700", "1800")))## year [tind]
## [1] 1700 1800Years as four-digit strings are indicated by %Y format
specifier. The last examples could also be written as:
(ys <- as.tind(c("1700", "1800", "1900", "2000", "2100"), format = "%Y"))## year [tind]
## [1] 1700 1800 1900 2000 2100Two-digit year indices are indicated by %y format
specifier. By default, numbers in range 69–99 are interpreted as years
1969–1999 and numbers 00–68 as years 2000–2068:
(ys <- as.tind(c("98", "99", "00", "01", "02"), format = "%y"))## year [tind]
## [1] 1998 1999 2000 2001 2002format(ys, "%Y")## [1] "1998" "1999" "2000" "2001" "2002"format(ys, "%y")## [1] "98" "99" "00" "01" "02"as.year guesses short year format:
(ys <- as.year(c("98", "99", "00", "01", "02")))## year [tind]
## [1] 1998 1999 2000 2001 2002Treatment of two-digit years is controlled by
tind.abbr.year.start option.
options("tind.abbr.year.start")## $tind.abbr.year.start
## [1] 69The internal code for quarters is q.
Quarters can be constructed using tind constructor with
arguments y and q. Arguments of
tind constructor are recycled if necessary.
(qs <- tind(y = rep(2020:2023, each = 4), q = 1:4))## quarter [tind]
## [1] 2020Q1 2020Q2 2020Q3 2020Q4 2021Q1 2021Q2 2021Q3 2021Q4 2022Q1 2022Q2
## [11] 2022Q3 2022Q4 2023Q1 2023Q2 2023Q3 2023Q4The default format for quarters is "%YQ%q", where
%q format specifier is a tind extension giving
quarter number. This will be automatically recognized:
(qs <- as.tind(c("2020Q1", "2020Q2", "2020Q3", "2020Q4")))## quarter [tind]
## [1] 2020Q1 2020Q2 2020Q3 2020Q4format(qs)## [1] "2020Q1" "2020Q2" "2020Q3" "2020Q4"format(qs, "%YQ%q")## [1] "2020Q1" "2020Q2" "2020Q3" "2020Q4"Less popular formats can be parsed using combinations of
%Y (or %y) and%q specifiers.
Consider YYYY.Q format:
as.tind("2023.2", format = "%Y.%q")## quarter [tind]
## [1] 2023Q2One can also specify the order of index components using
order argument:
as.tind("2023.2", order = "yq")## quarter [tind]
## [1] 2023Q2If order is yq, quarters will be automatically parsed if
type = "q" is set:
as.tind(c("2020 1", "2020 2", "2020 3", "2020 4"), type = "q")## quarter [tind]
## [1] 2020Q1 2020Q2 2020Q3 2020Q4Convenience function as.quarter is a shortcut for
as.tind(*, type = "q"):
as.quarter(c("2020 1", "2020 2", "2020 3", "2020 4"))## quarter [tind]
## [1] 2020Q1 2020Q2 2020Q3 2020Q4Packages stats and zoo (class
yearqrt) represent quarters as year fractions with e.g.,
2020.0, 2020.25, 2020.5,
2020.75 representing 2020Q1,
2020Q2, 2020Q3, 2020Q4
respectively. Conversion from this format can be done using
yf2tind function.
yf2tind(2020 + (0:3) / 4, "q")## quarter [tind]
## [1] 2020Q1 2020Q2 2020Q3 2020Q4The internal code for months is m.
Months can be constructed using tind constructor with
arguments y and m. Arguments of
tind constructor are recycled if necessary.
(ms <- tind(y = 2023, m = 1:12))## month [tind]
## [1] 2023-01 2023-02 2023-03 2023-04 2023-05 2023-06 2023-07 2023-08 2023-09
## [10] 2023-10 2023-11 2023-12The default format for months is "%Y-%m", where
%m format specifier represents month as a two-digit
number.
format(ms)## [1] "2023-01" "2023-02" "2023-03" "2023-04" "2023-05" "2023-06" "2023-07"
## [8] "2023-08" "2023-09" "2023-10" "2023-11" "2023-12"format(ms, "%Y-%m")## [1] "2023-01" "2023-02" "2023-03" "2023-04" "2023-05" "2023-06" "2023-07"
## [8] "2023-08" "2023-09" "2023-10" "2023-11" "2023-12"If order is ym, months will be automatically parsed if
type = "m" is set:
as.tind("2023-11", type = "m")## month [tind]
## [1] 2023-11Convenience function as.month is a shortcut for
as.tind(*, type = "m"):
as.month("2023-11")## month [tind]
## [1] 2023-11Format specifier %b denotes abbreviated month name as in
the following example. See documentation of month_names for
discussion of locale settings.
(shrtms <- format(ms, "%b %y", locale = "C"))## [1] "Jan 23" "Feb 23" "Mar 23" "Apr 23" "May 23" "Jun 23" "Jul 23" "Aug 23"
## [9] "Sep 23" "Oct 23" "Nov 23" "Dec 23"The above can be parsed using format specification or using order specification (with month first).
as.tind(shrtms, format = "%b %y", locale = "C")## month [tind]
## [1] 2023-01 2023-02 2023-03 2023-04 2023-05 2023-06 2023-07 2023-08 2023-09
## [10] 2023-10 2023-11 2023-12as.tind(shrtms, order = "my", locale = "C")## month [tind]
## [1] 2023-01 2023-02 2023-03 2023-04 2023-05 2023-06 2023-07 2023-08 2023-09
## [10] 2023-10 2023-11 2023-12Packages stats and zoo (class
yearmon) represent months as year fractions with e.g.,
2020.0, 2020.0833, 2020.1667,
2020.25 representing 2020-01,
2020-01, 2020-03, 2020-04
respectively. Conversion from this format can be done using
yf2tind function.
yf2tind(2020 + (0:11) / 12, "m")## month [tind]
## [1] 2020-01 2020-02 2020-03 2020-04 2020-05 2020-06 2020-07 2020-08 2020-09
## [10] 2020-10 2020-11 2020-12tind supports ISO 8610 weeks i.e. weeks starting on
Monday with the first week in a year being the week with the first
Thursday in a year. See https://en.wikipedia.org/wiki/ISO_week_date.
The internal code for weeks is w.
Weeks can be constructed using tind constructor with
arguments y and w. Arguments of
tind constructor are recycled if necessary.
(ws <- tind(y = 2024, w = 1:52))## week [tind]
## [1] 2024-W01 2024-W02 2024-W03 2024-W04 2024-W05 2024-W06 2024-W07 2024-W08
## [9] 2024-W09 2024-W10 2024-W11 2024-W12 2024-W13 2024-W14 2024-W15 2024-W16
## [17] 2024-W17 2024-W18 2024-W19 2024-W20 2024-W21 2024-W22 2024-W23 2024-W24
## [25] 2024-W25 2024-W26 2024-W27 2024-W28 2024-W29 2024-W30 2024-W31 2024-W32
## [33] 2024-W33 2024-W34 2024-W35 2024-W36 2024-W37 2024-W38 2024-W39 2024-W40
## [41] 2024-W41 2024-W42 2024-W43 2024-W44 2024-W45 2024-W46 2024-W47 2024-W48
## [49] 2024-W49 2024-W50 2024-W51 2024-W52The default format for weeks is %G-W%V, where
%G is the week-based year (ISO week-numbering year, ISO
year) and %V ISO week number.
format(ws)## [1] "2024-W01" "2024-W02" "2024-W03" "2024-W04" "2024-W05" "2024-W06"
## [7] "2024-W07" "2024-W08" "2024-W09" "2024-W10" "2024-W11" "2024-W12"
## [13] "2024-W13" "2024-W14" "2024-W15" "2024-W16" "2024-W17" "2024-W18"
## [19] "2024-W19" "2024-W20" "2024-W21" "2024-W22" "2024-W23" "2024-W24"
## [25] "2024-W25" "2024-W26" "2024-W27" "2024-W28" "2024-W29" "2024-W30"
## [31] "2024-W31" "2024-W32" "2024-W33" "2024-W34" "2024-W35" "2024-W36"
## [37] "2024-W37" "2024-W38" "2024-W39" "2024-W40" "2024-W41" "2024-W42"
## [43] "2024-W43" "2024-W44" "2024-W45" "2024-W46" "2024-W47" "2024-W48"
## [49] "2024-W49" "2024-W50" "2024-W51" "2024-W52"format(ws, format = "%G-W%V")## [1] "2024-W01" "2024-W02" "2024-W03" "2024-W04" "2024-W05" "2024-W06"
## [7] "2024-W07" "2024-W08" "2024-W09" "2024-W10" "2024-W11" "2024-W12"
## [13] "2024-W13" "2024-W14" "2024-W15" "2024-W16" "2024-W17" "2024-W18"
## [19] "2024-W19" "2024-W20" "2024-W21" "2024-W22" "2024-W23" "2024-W24"
## [25] "2024-W25" "2024-W26" "2024-W27" "2024-W28" "2024-W29" "2024-W30"
## [31] "2024-W31" "2024-W32" "2024-W33" "2024-W34" "2024-W35" "2024-W36"
## [37] "2024-W37" "2024-W38" "2024-W39" "2024-W40" "2024-W41" "2024-W42"
## [43] "2024-W43" "2024-W44" "2024-W45" "2024-W46" "2024-W47" "2024-W48"
## [49] "2024-W49" "2024-W50" "2024-W51" "2024-W52"Note that you cannot use %Y, %W, and
%U specifiers with weeks. ISO week-numbering year may
differ from Gregorian (i.e. calendar) year %Y.
%W and %U formats refer to non-ISO weeks and
are not supported.
as.week (a shortcut for
as.tind(*, type = "w")) automatically recognizes this
format.
as.week("2024-W51")## week [tind]
## [1] 2024-W51Dates (code d) can be most easily constructed from
y, m, and d components passed to
tind constructor. Order of arguments is irrelevant.
tind(m = 3, d = 15, y = 2024)## date [tind]
## [1] 2024-03-15(ds <- tind(y = 2024, m = rep(1:3, each = 2), d = c(1, 16)))## date [tind]
## [1] 2024-01-01 2024-01-16 2024-02-01 2024-02-16 2024-03-01 2024-03-16The default format for dates is %Y-%m-%d (ISO format,
shortcut %F).
format(ds)## [1] "2024-01-01" "2024-01-16" "2024-02-01" "2024-02-16" "2024-03-01"
## [6] "2024-03-16"format(ds, format = "%Y-%m-%d")## [1] "2024-01-01" "2024-01-16" "2024-02-01" "2024-02-16" "2024-03-01"
## [6] "2024-03-16"format(ds, format = "%F")## [1] "2024-01-01" "2024-01-16" "2024-02-01" "2024-02-16" "2024-03-01"
## [6] "2024-03-16"as.date (a shortcut for
as.tind(*, type = "d")) automatically recognizes this
format.
as.date("2024-12-31")## date [tind]
## [1] 2024-12-31US format %m/%d/%y (shortcut %D) is also
automatically recognized.
as.date("12/31/24")## date [tind]
## [1] 2024-12-31format(as.date("12/31/24"), "%m/%d/%y")## [1] "12/31/24"format(as.date("12/31/24"), "%D")## [1] "12/31/24"Month names can also be used. See documentation of
month_names for discussion of locale settings.
(chds <- format(ds, "%b %d, %y", locale = "C"))## [1] "Jan 01, 24" "Jan 16, 24" "Feb 01, 24" "Feb 16, 24" "Mar 01, 24"
## [6] "Mar 16, 24"as.tind(chds, order = "mdy", locale = "C")## date [tind]
## [1] 2024-01-01 2024-01-16 2024-02-01 2024-02-16 2024-03-01 2024-03-16Type h (as in hour) represents times between
midnight (00:00) and midnight of the next day (24:00).
Time of day can be constructed from H, M,
and S arguments passed to tind
constructor.
tind(H = 0:23)## time of day [tind]
## [1] 00:00 01:00 02:00 03:00 04:00 05:00 06:00 07:00 08:00 09:00 10:00 11:00
## [13] 12:00 13:00 14:00 15:00 16:00 17:00 18:00 19:00 20:00 21:00 22:00 23:00tind(H = 13, M = (0:3) * 15)## time of day [tind]
## [1] 13:00 13:15 13:30 13:45(tod1 <- tind(H = 13, M = 30, S = (0:11) * 5))## time of day [tind]
## [1] 13:30:00 13:30:05 13:30:10 13:30:15 13:30:20 13:30:25 13:30:30 13:30:35
## [9] 13:30:40 13:30:45 13:30:50 13:30:55Sub-second accuracy is also supported.
(tod2 <- tind(H = 13, M = 30, S = 17 + (0:9) / 10))## time of day [tind]
## [1] 13:30:17.0 13:30:17.1 13:30:17.2 13:30:17.3 13:30:17.4 13:30:17.5
## [7] 13:30:17.6 13:30:17.7 13:30:17.8 13:30:17.9As seen above, tind automatically determines whether
seconds should be shown or sub-second accuracy is required.
Format specifiers %H, %M, and
%S can be used with time of day.
format(tod1, "%H:%M")## [1] "13:30" "13:30" "13:30" "13:30" "13:30" "13:30" "13:30" "13:30" "13:30"
## [10] "13:30" "13:30" "13:30"format(tod1, "%H:%M:%S")## [1] "13:30:00" "13:30:05" "13:30:10" "13:30:15" "13:30:20" "13:30:25"
## [7] "13:30:30" "13:30:35" "13:30:40" "13:30:45" "13:30:50" "13:30:55"as.tind("13:47", format = "%H:%M")## time of day [tind]
## [1] 13:47as.tind("13:47:39", format = "%H:%M:%S")## time of day [tind]
## [1] 13:47:39Sub-second accuracy can be explicitly requested via
%OS[0-6] format specifier.
format(tod2, "%H:%M:%S")## [1] "13:30:17" "13:30:17" "13:30:17" "13:30:17" "13:30:17" "13:30:17"
## [7] "13:30:17" "13:30:17" "13:30:17" "13:30:17"format(tod2, "%H:%M:%OS1")## [1] "13:30:17.0" "13:30:17.1" "13:30:17.2" "13:30:17.3" "13:30:17.4"
## [6] "13:30:17.5" "13:30:17.6" "13:30:17.7" "13:30:17.8" "13:30:17.9"format(tod2, "%H:%M:%OS2")## [1] "13:30:17.00" "13:30:17.10" "13:30:17.20" "13:30:17.30" "13:30:17.40"
## [6] "13:30:17.50" "13:30:17.60" "13:30:17.70" "13:30:17.80" "13:30:17.90"format(tod2, "%H:%M:%OS3")## [1] "13:30:17.000" "13:30:17.100" "13:30:17.200" "13:30:17.300" "13:30:17.400"
## [6] "13:30:17.500" "13:30:17.600" "13:30:17.700" "13:30:17.800" "13:30:17.900"For parsing, %OS (without digits) should be used.
as.tind("13:47:39.89", format = "%H:%M:%OS")## time of day [tind]
## [1] 13:47:39.89H, M, and S can be used for
order specification. With order specifier S sub-second
accuracy is automatically determined.
as.tind("13", order = "H")## time of day [tind]
## [1] 13:00as.tind("13:47", order = "HM")## time of day [tind]
## [1] 13:47as.tind("13:47:39", order = "HMS")## time of day [tind]
## [1] 13:47:39as.tind("13:47:39.9", order = "HMS")## time of day [tind]
## [1] 13:47:39.9as.tind("13:47:39.89", order = "HMS")## time of day [tind]
## [1] 13:47:39.8912-hour clock can be used with the help of %I (hour in
12-hour clock) and %p (ante meridiem, post meridiem)
specifiers.
format(tind(H = 0:23), "%I %p")## [1] "12 am" "01 am" "02 am" "03 am" "04 am" "05 am" "06 am" "07 am" "08 am"
## [10] "09 am" "10 am" "11 am" "12 pm" "01 pm" "02 pm" "03 pm" "04 pm" "05 pm"
## [19] "06 pm" "07 pm" "08 pm" "09 pm" "10 pm" "11 pm"as.tind("9:30am", format = "%I:%M%p")## time of day [tind]
## [1] 09:30Alternatively, I and p order specifiers can
be used.
as.tind("9:30am", order = "IMp")## time of day [tind]
## [1] 09:30Date-time indices (code t) can be constructed from
components required for date and at least hour (H)
component.
tind(y = 2024, m = 8, d = 2, H = 16)## date-time, time zone: Europe/Warsaw [tind]
## [1] 2024-08-02 16:00 CESTtind(y = 2024, m = 8, d = 2, H = 16, M = (0:3) * 15)## date-time, time zone: Europe/Warsaw [tind]
## [1] 2024-08-02 16:00 CEST 2024-08-02 16:15 CEST 2024-08-02 16:30 CEST
## [4] 2024-08-02 16:45 CESTtind(y = 2024, m = 8, d = 2, H = 16, M = 0, S = 10 * (0:5))## date-time, time zone: Europe/Warsaw [tind]
## [1] 2024-08-02 16:00:00 CEST 2024-08-02 16:00:10 CEST
## [3] 2024-08-02 16:00:20 CEST 2024-08-02 16:00:30 CEST
## [5] 2024-08-02 16:00:40 CEST 2024-08-02 16:00:50 CESTAll date-time indices always have time zone attribute set. For more
information, see documentation of tzone function. By
default, time zone is set to system time zone but can be explicitly set
using tz argument.
tind(y = 2024, m = 8, d = 2, H = 16, M = (0:3) * 15, tz = "UTC")## date-time, time zone: UTC [tind]
## [1] 2024-08-02 16:00 UTC 2024-08-02 16:15 UTC 2024-08-02 16:30 UTC
## [4] 2024-08-02 16:45 UTCDate-time indices can also be constructed from date and time of day
indices using date_time function.
(dt1 <- date_time(tind(y = 2024, m = 8, d = 2),
tind(H = 16, M = (0:3) * 15)))## date-time, time zone: Europe/Warsaw [tind]
## [1] 2024-08-02 16:00 CEST 2024-08-02 16:15 CEST 2024-08-02 16:30 CEST
## [4] 2024-08-02 16:45 CEST(dt2 <- date_time(tind(y = 2024, m = 8, d = 2),
tind(H = 16, M = (0:3) * 15), tz = "UTC"))## date-time, time zone: UTC [tind]
## [1] 2024-08-02 16:00 UTC 2024-08-02 16:15 UTC 2024-08-02 16:30 UTC
## [4] 2024-08-02 16:45 UTCReverse operation can be performed using date_time_split
function.
date_time_split(dt1)## $date
## date [tind]
## [1] 2024-08-02 2024-08-02 2024-08-02 2024-08-02
##
## $time
## time of day [tind]
## [1] 16:00 16:15 16:30 16:45As lists can be trivially converted to data frames, if a data frame
is desired, date_time_split only has to be wrapped by
as.data.frame.
as.data.frame(date_time_split(dt1))## date time
## 1 2024-08-02 16:00
## 2 2024-08-02 16:15
## 3 2024-08-02 16:30
## 4 2024-08-02 16:45As seen, formatting of date-time indices depends on actual indices
(need for seconds or for subsecond accuracy). Moreover,
as.character and format methods differ. The
former returns UTC offset (or Z for UTC), the latter time
zone abbreviation.
as.character(dt1)## [1] "2024-08-02 16:00+0200" "2024-08-02 16:15+0200" "2024-08-02 16:30+0200"
## [4] "2024-08-02 16:45+0200"as.character(dt2)## [1] "2024-08-02 16:00Z" "2024-08-02 16:15Z" "2024-08-02 16:30Z"
## [4] "2024-08-02 16:45Z"format(dt1)## [1] "2024-08-02 16:00 CEST" "2024-08-02 16:15 CEST" "2024-08-02 16:30 CEST"
## [4] "2024-08-02 16:45 CEST"format(dt2)## [1] "2024-08-02 16:00 UTC" "2024-08-02 16:15 UTC" "2024-08-02 16:30 UTC"
## [4] "2024-08-02 16:45 UTC"All format specifiers that can be used with dates and time of day can
also be used with date-time. %z specifier represents UTC
offset, %Z returns time zone abbreviation.
format(dt1, "%F %H:%M")## [1] "2024-08-02 16:00" "2024-08-02 16:15" "2024-08-02 16:30" "2024-08-02 16:45"format(dt1, "%F %H:%M%z")## [1] "2024-08-02 16:00+0200" "2024-08-02 16:15+0200" "2024-08-02 16:30+0200"
## [4] "2024-08-02 16:45+0200"format(dt1, "%F %H:%M %Z")## [1] "2024-08-02 16:00 CEST" "2024-08-02 16:15 CEST" "2024-08-02 16:30 CEST"
## [4] "2024-08-02 16:45 CEST"format(dt1, "%D %I:%M%p")## [1] "08/02/24 04:00pm" "08/02/24 04:15pm" "08/02/24 04:30pm" "08/02/24 04:45pm"Standard formats are automatically recognized during parsing.
as.tind("2025-02-01 13:03")## date-time, time zone: Europe/Warsaw [tind]
## [1] 2025-02-01 13:03 CETas.tind("2025-02-01 13:03:34")## date-time, time zone: Europe/Warsaw [tind]
## [1] 2025-02-01 13:03:34 CETas.tind("2025-02-01 13:03:34.534")## date-time, time zone: Europe/Warsaw [tind]
## [1] 2025-02-01 13:03:34.534 CETWhen converting to tind, either format or
order arguments can be provided.
as.tind("2025-02-01 13:03:34.534", format = "%F %H:%M:%OS")## date-time, time zone: Europe/Warsaw [tind]
## [1] 2025-02-01 13:03:34.534 CETas.tind("02/01/25 01:03:34pm", format = "%D %I:%M:%OS%p")## date-time, time zone: Europe/Warsaw [tind]
## [1] 2025-02-01 13:03:34 CETas.tind("2025-02-01 13:03:34.534", order = "ymdHMS")## date-time, time zone: Europe/Warsaw [tind]
## [1] 2025-02-01 13:03:34.534 CETas.tind("2025-02-01 13:03:34.534", order = "ymdHMS", tz = "UTC")## date-time, time zone: UTC [tind]
## [1] 2025-02-01 13:03:34.534 UTCas.tind("02/01/25 01:03:34pm", order = "mdyIMSp")## date-time, time zone: Europe/Warsaw [tind]
## [1] 2025-02-01 13:03:34 CETas.tind("02/01/25 01:03:34pm", order = "mdyIMSp", tz = "UTC")## date-time, time zone: UTC [tind]
## [1] 2025-02-01 13:03:34 UTCThe parser recognizes time zone abbreviations:
as.tind("2025-02-22 09:54:04 CET", tz = "Europe/Warsaw")## date-time, time zone: Europe/Warsaw [tind]
## [1] 2025-02-22 09:54:04 CETas.tind("2025-08-23 09:54:04 CEST", tz = "Europe/Warsaw")## date-time, time zone: Europe/Warsaw [tind]
## [1] 2025-08-23 09:54:04 CESTas.tind("2/22/25 9:54 a.m. EST", order = "mdyIMpz", tz = "America/New_York")## date-time, time zone: America/New_York [tind]
## [1] 2025-02-22 09:54 ESTas.tind("8/23/25 9:54 a.m. EDT", order = "mdyIMpz", tz = "America/New_York")## date-time, time zone: America/New_York [tind]
## [1] 2025-08-23 09:54 EDTWhen time zone is not provided, the parser tries to guess the time zone:
as.tind("2025-02-22 09:54:04 CET")## date-time, time zone: Europe/Warsaw [tind]
## [1] 2025-02-22 09:54:04 CETas.tind("2025-08-23 09:54:04 CEST")## date-time, time zone: Europe/Warsaw [tind]
## [1] 2025-08-23 09:54:04 CESTas.tind("2/22/25 9:54 a.m. EST", order = "mdyIMpz")## date-time, time zone: America/New_York [tind]
## [1] 2025-02-22 09:54 ESTas.tind("8/23/25 9:54 a.m. EDT", order = "mdyIMpz")## date-time, time zone: America/New_York [tind]
## [1] 2025-08-23 09:54 EDTWhen time zone abbreviation can denote different UTC offsets
(unfortunately, this can be the case) NAs are introduced
with a warning.
For completeness, tind supports arbitrary integer
indices (code i) and arbitrary numeric indices (code
n).
as.tind(0:9, type = "i")## integer index [tind]
## [1] 0 1 2 3 4 5 6 7 8 9as.tind(0:9 / 10, type = "n")## numeric index [tind]
## [1] 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9Time index conversion is extremely easy with tind class.
as.tind method as well as as.year,
as.date, etc. convenience functions can be used for
this.
ms## month [tind]
## [1] 2023-01 2023-02 2023-03 2023-04 2023-05 2023-06 2023-07 2023-08 2023-09
## [10] 2023-10 2023-11 2023-12as.quarter(ms)## quarter [tind]
## [1] 2023Q1 2023Q1 2023Q1 2023Q2 2023Q2 2023Q2 2023Q3 2023Q3 2023Q3 2023Q4
## [11] 2023Q4 2023Q4as.year(ms)## year [tind]
## [1] 2023 2023 2023 2023 2023 2023 2023 2023 2023 2023 2023 2023as.date(ms)## date [tind]
## [1] 2023-01-01 2023-02-01 2023-03-01 2023-04-01 2023-05-01 2023-06-01
## [7] 2023-07-01 2023-08-01 2023-09-01 2023-10-01 2023-11-01 2023-12-01as.date_time(ms)## date-time, time zone: Europe/Warsaw [tind]
## [1] 2023-01-01 00:00 CET 2023-02-01 00:00 CET 2023-03-01 00:00 CET
## [4] 2023-04-01 00:00 CEST 2023-05-01 00:00 CEST 2023-06-01 00:00 CEST
## [7] 2023-07-01 00:00 CEST 2023-08-01 00:00 CEST 2023-09-01 00:00 CEST
## [10] 2023-10-01 00:00 CEST 2023-11-01 00:00 CET 2023-12-01 00:00 CETas.date_time(ms, tz = "UTC")## date-time, time zone: UTC [tind]
## [1] 2023-01-01 00:00 UTC 2023-02-01 00:00 UTC 2023-03-01 00:00 UTC
## [4] 2023-04-01 00:00 UTC 2023-05-01 00:00 UTC 2023-06-01 00:00 UTC
## [7] 2023-07-01 00:00 UTC 2023-08-01 00:00 UTC 2023-09-01 00:00 UTC
## [10] 2023-10-01 00:00 UTC 2023-11-01 00:00 UTC 2023-12-01 00:00 UTCas.Date, as.POSIXct, and
as.POSIXlt can be used to convert time indices to base R
date and date-time classes.
ds## date [tind]
## [1] 2024-01-01 2024-01-16 2024-02-01 2024-02-16 2024-03-01 2024-03-16as.Date(ds)## [1] "2024-01-01" "2024-01-16" "2024-02-01" "2024-02-16" "2024-03-01"
## [6] "2024-03-16"dt1## date-time, time zone: Europe/Warsaw [tind]
## [1] 2024-08-02 16:00 CEST 2024-08-02 16:15 CEST 2024-08-02 16:30 CEST
## [4] 2024-08-02 16:45 CESTas.POSIXct(dt1)## [1] "2024-08-02 16:00:00 CEST" "2024-08-02 16:15:00 CEST"
## [3] "2024-08-02 16:30:00 CEST" "2024-08-02 16:45:00 CEST"dt2## date-time, time zone: UTC [tind]
## [1] 2024-08-02 16:00 UTC 2024-08-02 16:15 UTC 2024-08-02 16:30 UTC
## [4] 2024-08-02 16:45 UTCas.POSIXlt(dt2)## [1] "2024-08-02 16:00:00 UTC" "2024-08-02 16:15:00 UTC"
## [3] "2024-08-02 16:30:00 UTC" "2024-08-02 16:45:00 UTC"cut Methodmatch_t function and %in_t% operator allow
to match time indices to another set of time indices, possibly of
different type (lower resolution).
In the following example, a sequence of dates is matched to months:
(x <- as.date("2025-03-02") + 15 * (0:5))## date [tind]
## [1] 2025-03-02 2025-03-17 2025-04-01 2025-04-16 2025-05-01 2025-05-16(table <- as.month("2025-03") + -1:1)## month [tind]
## [1] 2025-02 2025-03 2025-04match_t(x, table)## [1] 2 2 3 3 NA NABelow we check which dates fall in March 2025:
x %in_t% "2025-03"## [1] TRUE TRUE FALSE FALSE FALSE FALSEComparison operators (e.g., >, >=)
can be used to compare time indices. Below we check which dates fall in
or after April 2025 and before April 2025:
x >= "2025-04"## [1] FALSE FALSE TRUE TRUE TRUE TRUEx < "2025-04"## [1] TRUE TRUE FALSE FALSE FALSE FALSEcut method for object of tind class divides
time indices into periods. Using x from the last example,
we can split dates into months and quarters:
cut(x, "m")## [1] 2025-03 2025-03 2025-04 2025-04 2025-05 2025-05
## Levels: 2025-03 < 2025-04 < 2025-05cut(x, "q")## [1] 2025Q1 2025Q1 2025Q2 2025Q2 2025Q2 2025Q2
## Levels: 2025Q1 < 2025Q2