R Under development (unstable) (2023-03-21 r84017) -- "Unsuffered Consequences"
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> ### Tests of often platform-dependent features of the POSIX[cl]t implementation.
>
> ### Expect differences, especially with 32-bit time_t and platforms
> ### without tm_zone/tm_gmtoff.
>
> z <- ISOdate(1890:1912, 1, 10, tz="UTC")
> ## Rome changed to CET for 1894
> as.POSIXlt(z, tz="Europe/Rome")
[1] "1890-01-10 12:49:56 RMT" "1891-01-10 12:49:56 RMT"
[3] "1892-01-10 12:49:56 RMT" "1893-01-10 12:49:56 RMT"
[5] "1894-01-10 13:00:00 CET" "1895-01-10 13:00:00 CET"
[7] "1896-01-10 13:00:00 CET" "1897-01-10 13:00:00 CET"
[9] "1898-01-10 13:00:00 CET" "1899-01-10 13:00:00 CET"
[11] "1900-01-10 13:00:00 CET" "1901-01-10 13:00:00 CET"
[13] "1902-01-10 13:00:00 CET" "1903-01-10 13:00:00 CET"
[15] "1904-01-10 13:00:00 CET" "1905-01-10 13:00:00 CET"
[17] "1906-01-10 13:00:00 CET" "1907-01-10 13:00:00 CET"
[19] "1908-01-10 13:00:00 CET" "1909-01-10 13:00:00 CET"
[21] "1910-01-10 13:00:00 CET" "1911-01-10 13:00:00 CET"
[23] "1912-01-10 13:00:00 CET"
> ## Paris changed to PMT for 1892, WET for 1912
> (zz <- as.POSIXlt(z, tz="Europe/Paris"))
[1] "1890-01-10 12:09:21 LMT" "1891-01-10 12:09:21 LMT"
[3] "1892-01-10 12:09:21 PMT" "1893-01-10 12:09:21 PMT"
[5] "1894-01-10 12:09:21 PMT" "1895-01-10 12:09:21 PMT"
[7] "1896-01-10 12:09:21 PMT" "1897-01-10 12:09:21 PMT"
[9] "1898-01-10 12:09:21 PMT" "1899-01-10 12:09:21 PMT"
[11] "1900-01-10 12:09:21 PMT" "1901-01-10 12:09:21 PMT"
[13] "1902-01-10 12:09:21 PMT" "1903-01-10 12:09:21 PMT"
[15] "1904-01-10 12:09:21 PMT" "1905-01-10 12:09:21 PMT"
[17] "1906-01-10 12:09:21 PMT" "1907-01-10 12:09:21 PMT"
[19] "1908-01-10 12:09:21 PMT" "1909-01-10 12:09:21 PMT"
[21] "1910-01-10 12:09:21 PMT" "1911-01-10 12:09:21 PMT"
[23] "1912-01-10 12:00:00 WET"
> strftime(zz, "%Y-%m-%d %H:%M:%S %Z")
[1] "1890-01-10 12:09:21 LMT" "1891-01-10 12:09:21 LMT"
[3] "1892-01-10 12:09:21 PMT" "1893-01-10 12:09:21 PMT"
[5] "1894-01-10 12:09:21 PMT" "1895-01-10 12:09:21 PMT"
[7] "1896-01-10 12:09:21 PMT" "1897-01-10 12:09:21 PMT"
[9] "1898-01-10 12:09:21 PMT" "1899-01-10 12:09:21 PMT"
[11] "1900-01-10 12:09:21 PMT" "1901-01-10 12:09:21 PMT"
[13] "1902-01-10 12:09:21 PMT" "1903-01-10 12:09:21 PMT"
[15] "1904-01-10 12:09:21 PMT" "1905-01-10 12:09:21 PMT"
[17] "1906-01-10 12:09:21 PMT" "1907-01-10 12:09:21 PMT"
[19] "1908-01-10 12:09:21 PMT" "1909-01-10 12:09:21 PMT"
[21] "1910-01-10 12:09:21 PMT" "1911-01-10 12:09:21 PMT"
[23] "1912-01-10 12:00:00 WET"
> ## The offset was really +00:09:21 until 1911, then +00:00
> ## Many platforms will give the current offset, +0100
> strftime(zz, "%Y-%m-%d %H:%M:%S %z")
[1] "1890-01-10 12:09:21 +0009" "1891-01-10 12:09:21 +0009"
[3] "1892-01-10 12:09:21 +0009" "1893-01-10 12:09:21 +0009"
[5] "1894-01-10 12:09:21 +0009" "1895-01-10 12:09:21 +0009"
[7] "1896-01-10 12:09:21 +0009" "1897-01-10 12:09:21 +0009"
[9] "1898-01-10 12:09:21 +0009" "1899-01-10 12:09:21 +0009"
[11] "1900-01-10 12:09:21 +0009" "1901-01-10 12:09:21 +0009"
[13] "1902-01-10 12:09:21 +0009" "1903-01-10 12:09:21 +0009"
[15] "1904-01-10 12:09:21 +0009" "1905-01-10 12:09:21 +0009"
[17] "1906-01-10 12:09:21 +0009" "1907-01-10 12:09:21 +0009"
[19] "1908-01-10 12:09:21 +0009" "1909-01-10 12:09:21 +0009"
[21] "1910-01-10 12:09:21 +0009" "1911-01-10 12:09:21 +0009"
[23] "1912-01-10 12:00:00 +0000"
>
> ## Some platforms give details of the latest conversion.
> z <- ISOdate(c(seq(1890, 1940, 5), 1941:1946, 1950), 1, 10, tz="UTC")
> as.POSIXlt(z, tz="Europe/Paris")
[1] "1890-01-10 12:09:21 LMT" "1895-01-10 12:09:21 PMT"
[3] "1900-01-10 12:09:21 PMT" "1905-01-10 12:09:21 PMT"
[5] "1910-01-10 12:09:21 PMT" "1915-01-10 12:00:00 WET"
[7] "1920-01-10 12:00:00 WET" "1925-01-10 12:00:00 WET"
[9] "1930-01-10 12:00:00 WET" "1935-01-10 12:00:00 WET"
[11] "1940-01-10 12:00:00 WET" "1941-01-10 14:00:00 CEST"
[13] "1942-01-10 14:00:00 CEST" "1943-01-10 13:00:00 CET"
[15] "1944-01-10 13:00:00 CET" "1945-01-10 13:00:00 WEST"
[17] "1946-01-10 13:00:00 CET" "1950-01-10 13:00:00 CET"
> for(i in seq_along(z)) print(as.POSIXlt(z[i], tz="Europe/Paris"))
[1] "1890-01-10 12:09:21 LMT"
[1] "1895-01-10 12:09:21 PMT"
[1] "1900-01-10 12:09:21 PMT"
[1] "1905-01-10 12:09:21 PMT"
[1] "1910-01-10 12:09:21 PMT"
[1] "1915-01-10 12:00:00 WET"
[1] "1920-01-10 12:00:00 WET"
[1] "1925-01-10 12:00:00 WET"
[1] "1930-01-10 12:00:00 WET"
[1] "1935-01-10 12:00:00 WET"
[1] "1940-01-10 12:00:00 WET"
[1] "1941-01-10 14:00:00 CEST"
[1] "1942-01-10 14:00:00 CEST"
[1] "1943-01-10 13:00:00 CET"
[1] "1944-01-10 13:00:00 CET"
[1] "1945-01-10 13:00:00 WEST"
[1] "1946-01-10 13:00:00 CET"
[1] "1950-01-10 13:00:00 CET"
> ## use pf %z needs tm_gmtoff
> for(i in seq_along(z))
+ print(strftime(as.POSIXlt(z[i], tz="Europe/Paris"), "%Y-%m-%d %H:%M:%S %z"))
[1] "1890-01-10 12:09:21 +0009"
[1] "1895-01-10 12:09:21 +0009"
[1] "1900-01-10 12:09:21 +0009"
[1] "1905-01-10 12:09:21 +0009"
[1] "1910-01-10 12:09:21 +0009"
[1] "1915-01-10 12:00:00 +0000"
[1] "1920-01-10 12:00:00 +0000"
[1] "1925-01-10 12:00:00 +0000"
[1] "1930-01-10 12:00:00 +0000"
[1] "1935-01-10 12:00:00 +0000"
[1] "1940-01-10 12:00:00 +0000"
[1] "1941-01-10 14:00:00 +0200"
[1] "1942-01-10 14:00:00 +0200"
[1] "1943-01-10 13:00:00 +0100"
[1] "1944-01-10 13:00:00 +0100"
[1] "1945-01-10 13:00:00 +0100"
[1] "1946-01-10 13:00:00 +0100"
[1] "1950-01-10 13:00:00 +0100"
>
> strptime("1920-12-27 08:18:23", "%Y-%m-%d %H:%M:%S", tz="Europe/Paris")
[1] "1920-12-27 08:18:23 WET"
>
> ## check %V etc
>
> d <- expand.grid(day = 1:7, year = 2000:2010)
> z1 <- with(d, ISOdate(year, 1, day))
> d <- expand.grid(day = 25:31, year = 2000:2010)
> z2 <- with(d, ISOdate(year, 12, day))
> z <- sort(c(z1, z2))
> strftime(z, "%G %g %W %U %u %V %W %w", tz="Europe/Paris")
[1] "1999 99 00 00 6 52 00 6" "1999 99 00 01 7 52 00 0"
[3] "2000 00 01 01 1 01 01 1" "2000 00 01 01 2 01 01 2"
[5] "2000 00 01 01 3 01 01 3" "2000 00 01 01 4 01 01 4"
[7] "2000 00 01 01 5 01 01 5" "2000 00 52 52 1 52 52 1"
[9] "2000 00 52 52 2 52 52 2" "2000 00 52 52 3 52 52 3"
[11] "2000 00 52 52 4 52 52 4" "2000 00 52 52 5 52 52 5"
[13] "2000 00 52 52 6 52 52 6" "2000 00 52 53 7 52 52 0"
[15] "2001 01 01 00 1 01 01 1" "2001 01 01 00 2 01 01 2"
[17] "2001 01 01 00 3 01 01 3" "2001 01 01 00 4 01 01 4"
[19] "2001 01 01 00 5 01 01 5" "2001 01 01 00 6 01 01 6"
[21] "2001 01 01 01 7 01 01 0" "2001 01 52 51 2 52 52 2"
[23] "2001 01 52 51 3 52 52 3" "2001 01 52 51 4 52 52 4"
[25] "2001 01 52 51 5 52 52 5" "2001 01 52 51 6 52 52 6"
[27] "2001 01 52 52 7 52 52 0" "2002 02 53 52 1 01 53 1"
[29] "2002 02 00 00 2 01 00 2" "2002 02 00 00 3 01 00 3"
[31] "2002 02 00 00 4 01 00 4" "2002 02 00 00 5 01 00 5"
[33] "2002 02 00 00 6 01 00 6" "2002 02 00 01 7 01 00 0"
[35] "2002 02 01 01 1 02 01 1" "2002 02 51 51 3 52 51 3"
[37] "2002 02 51 51 4 52 51 4" "2002 02 51 51 5 52 51 5"
[39] "2002 02 51 51 6 52 51 6" "2002 02 51 52 7 52 51 0"
[41] "2003 03 52 52 1 01 52 1" "2003 03 52 52 2 01 52 2"
[43] "2003 03 00 00 3 01 00 3" "2003 03 00 00 4 01 00 4"
[45] "2003 03 00 00 5 01 00 5" "2003 03 00 00 6 01 00 6"
[47] "2003 03 00 01 7 01 00 0" "2003 03 01 01 1 02 01 1"
[49] "2003 03 01 01 2 02 01 2" "2003 03 51 51 4 52 51 4"
[51] "2003 03 51 51 5 52 51 5" "2003 03 51 51 6 52 51 6"
[53] "2003 03 51 52 7 52 51 0" "2004 04 52 52 1 01 52 1"
[55] "2004 04 52 52 2 01 52 2" "2004 04 52 52 3 01 52 3"
[57] "2004 04 00 00 4 01 00 4" "2004 04 00 00 5 01 00 5"
[59] "2004 04 00 00 6 01 00 6" "2004 04 00 01 7 01 00 0"
[61] "2004 04 01 01 1 02 01 1" "2004 04 01 01 2 02 01 2"
[63] "2004 04 01 01 3 02 01 3" "2004 04 51 51 6 52 51 6"
[65] "2004 04 51 52 7 52 51 0" "2004 04 52 52 1 53 52 1"
[67] "2004 04 52 52 2 53 52 2" "2004 04 52 52 3 53 52 3"
[69] "2004 04 52 52 4 53 52 4" "2004 04 52 52 5 53 52 5"
[71] "2004 04 00 00 6 53 00 6" "2004 04 00 01 7 53 00 0"
[73] "2005 05 01 01 1 01 01 1" "2005 05 01 01 2 01 01 2"
[75] "2005 05 01 01 3 01 01 3" "2005 05 01 01 4 01 01 4"
[77] "2005 05 01 01 5 01 01 5" "2005 05 51 52 7 51 51 0"
[79] "2005 05 52 52 1 52 52 1" "2005 05 52 52 2 52 52 2"
[81] "2005 05 52 52 3 52 52 3" "2005 05 52 52 4 52 52 4"
[83] "2005 05 52 52 5 52 52 5" "2005 05 52 52 6 52 52 6"
[85] "2005 05 00 01 7 52 00 0" "2006 06 01 01 1 01 01 1"
[87] "2006 06 01 01 2 01 01 2" "2006 06 01 01 3 01 01 3"
[89] "2006 06 01 01 4 01 01 4" "2006 06 01 01 5 01 01 5"
[91] "2006 06 01 01 6 01 01 6" "2006 06 52 52 1 52 52 1"
[93] "2006 06 52 52 2 52 52 2" "2006 06 52 52 3 52 52 3"
[95] "2006 06 52 52 4 52 52 4" "2006 06 52 52 5 52 52 5"
[97] "2006 06 52 52 6 52 52 6" "2006 06 52 53 7 52 52 0"
[99] "2007 07 01 00 1 01 01 1" "2007 07 01 00 2 01 01 2"
[101] "2007 07 01 00 3 01 01 3" "2007 07 01 00 4 01 01 4"
[103] "2007 07 01 00 5 01 01 5" "2007 07 01 00 6 01 01 6"
[105] "2007 07 01 01 7 01 01 0" "2007 07 52 51 2 52 52 2"
[107] "2007 07 52 51 3 52 52 3" "2007 07 52 51 4 52 52 4"
[109] "2007 07 52 51 5 52 52 5" "2007 07 52 51 6 52 52 6"
[111] "2007 07 52 52 7 52 52 0" "2008 08 53 52 1 01 53 1"
[113] "2008 08 00 00 2 01 00 2" "2008 08 00 00 3 01 00 3"
[115] "2008 08 00 00 4 01 00 4" "2008 08 00 00 5 01 00 5"
[117] "2008 08 00 00 6 01 00 6" "2008 08 00 01 7 01 00 0"
[119] "2008 08 01 01 1 02 01 1" "2008 08 51 51 4 52 51 4"
[121] "2008 08 51 51 5 52 51 5" "2008 08 51 51 6 52 51 6"
[123] "2008 08 51 52 7 52 51 0" "2009 09 52 52 1 01 52 1"
[125] "2009 09 52 52 2 01 52 2" "2009 09 52 52 3 01 52 3"
[127] "2009 09 00 00 4 01 00 4" "2009 09 00 00 5 01 00 5"
[129] "2009 09 00 00 6 01 00 6" "2009 09 00 01 7 01 00 0"
[131] "2009 09 01 01 1 02 01 1" "2009 09 01 01 2 02 01 2"
[133] "2009 09 01 01 3 02 01 3" "2009 09 51 51 5 52 51 5"
[135] "2009 09 51 51 6 52 51 6" "2009 09 51 52 7 52 51 0"
[137] "2009 09 52 52 1 53 52 1" "2009 09 52 52 2 53 52 2"
[139] "2009 09 52 52 3 53 52 3" "2009 09 52 52 4 53 52 4"
[141] "2009 09 00 00 5 53 00 5" "2009 09 00 00 6 53 00 6"
[143] "2009 09 00 01 7 53 00 0" "2010 10 01 01 1 01 01 1"
[145] "2010 10 01 01 2 01 01 2" "2010 10 01 01 3 01 01 3"
[147] "2010 10 01 01 4 01 01 4" "2010 10 51 51 6 51 51 6"
[149] "2010 10 51 52 7 51 51 0" "2010 10 52 52 1 52 52 1"
[151] "2010 10 52 52 2 52 52 2" "2010 10 52 52 3 52 52 3"
[153] "2010 10 52 52 4 52 52 4" "2010 10 52 52 5 52 52 5"
>
> ## tests of earlier years. Default format is OS-dependent, so don't test it.
> ## ISOdate only accepts positive years.
> z <- as.Date(ISOdate(c(0, 8, 9, 10, 11, 20, 110, 1010), 1, 10)) - 3630
> strftime(z, "%04Y-%m-%d") # with leading zero(s), where supported
[1] "-010-02-01" "-002-02-01" "-001-02-02" "0000-02-02" "0001-02-01"
[6] "0010-02-01" "0100-02-01" "1000-02-01"
> strftime(z, "%_4Y-%m-%d") # with leading space(s), where supported
[1] " -10-02-01" " -2-02-01" " -1-02-02" " 0-02-02" " 1-02-01"
[6] " 10-02-01" " 100-02-01" "1000-02-01"
> strftime(z, "%0Y-%m-%d") # without
[1] "-10-02-01" "-2-02-01" "-1-02-02" "0-02-02" "1-02-01"
[6] "10-02-01" "100-02-01" "1000-02-01"
>
>
> ## more test of strftime
> x <- ISOdate(2014, 3, 10, c(7, 13))
> fmts <- c("%Y-%m-%d %H:%M:%S", "%F", "%A %a %b %h %e %I %j",
+ ## locale-dependent ones
+ "%X", # but the same in all English locales
+ "%c", "%x", "%p", "%r")
> for (f in fmts) print(format(x, f))
[1] "2014-03-10 07:00:00" "2014-03-10 13:00:00"
[1] "2014-03-10" "2014-03-10"
[1] "Monday Mon Mar Mar 10 07 069" "Monday Mon Mar Mar 10 01 069"
[1] "07:00:00" "13:00:00"
[1] "Mon Mar 10 07:00:00 2014" "Mon Mar 10 13:00:00 2014"
[1] "03/10/14" "03/10/14"
[1] "AM" "PM"
[1] "07:00:00 AM" "01:00:00 PM"
>
> ## Moved from reg-tests-1d.R
> ## as.POSIXlt(<very large Date>) gave integer overflow
> ## and needed C-level change for 32-bit time_t.
> .Machine$sizeof.time_t
[1] 8
> (z <- .Date(2^31 + 10))
[1] "5881580-07-22"
> as.POSIXlt(z)$year == 5879680L
[1] TRUE
> ## year was negative in R <= 4.2.1, even for 64-bit time_t
>
>
> ## ------------- Tests of far-distant dates -----------
> Sys.setenv(TZ = "Europe/London")
> ## the pre-1902 POSIXct values wil be 75s out on platdorm that do not
> ## know about UK changes prior to 1902 (in fact in 1847-12-01: see below).
> as.POSIXct("4000-07-01")
[1] "4000-07-01 BST"
> as.Date("4000-07-01")
[1] "4000-07-01"
> zz <- z <- as.POSIXlt("2000-07-01")
> unclass(z)
$sec
[1] 0
$min
[1] 0
$hour
[1] 0
$mday
[1] 1
$mon
[1] 6
$year
[1] 100
$wday
[1] 6
$yday
[1] 182
$isdst
[1] 1
$zone
[1] "BST"
$gmtoff
[1] NA
attr(,"tzone")
[1] "Europe/London" "GMT" "BST"
attr(,"balanced")
[1] TRUE
>
> years <- c(-1e6, -1e5, -1e4, seq(-1000, 4000, by = 100), 1e4, 1e5, 1e6)
> y <- character(length(years))
> for(i in seq_along(years)) {
+ zz$year = years[i] - 1900
+ y[i] <- strftime(zz)
+ }
> ## IGNORE_RDIFF_BEGIN
> y
[1] "-1000000-07-01" "-100000-07-01" "-10000-07-01" "-1000-07-01"
[5] "-900-07-01" "-800-07-01" "-700-07-01" "-600-07-01"
[9] "-500-07-01" "-400-07-01" "-300-07-01" "-200-07-01"
[13] "-100-07-01" "0000-07-01" "0100-07-01" "0200-07-01"
[17] "0300-07-01" "0400-07-01" "0500-07-01" "0600-07-01"
[21] "0700-07-01" "0800-07-01" "0900-07-01" "1000-07-01"
[25] "1100-07-01" "1200-07-01" "1300-07-01" "1400-07-01"
[29] "1500-07-01" "1600-07-01" "1700-07-01" "1800-07-01"
[33] "1900-07-01" "2000-07-01" "2100-07-01" "2200-07-01"
[37] "2300-07-01" "2400-07-01" "2500-07-01" "2600-07-01"
[41] "2700-07-01" "2800-07-01" "2900-07-01" "3000-07-01"
[45] "3100-07-01" "3200-07-01" "3300-07-01" "3400-07-01"
[49] "3500-07-01" "3600-07-01" "3700-07-01" "3800-07-01"
[53] "3900-07-01" "4000-07-01" "10000-07-01" "100000-07-01"
[57] "1000000-07-01"
> ## IGNORE_RDIFF_END
>
> y <- double(length(years))
> for(i in seq_along(years)) {
+ zz$year = years[i] - 1900
+ zz$isdst <- -1 # some are DST, some not so let the code decide
+ y[i] <- as.POSIXct(zz)
+ }
> print(y, digits=14)
[1] -31619103494325 -3217846694325 -377721014325 -93708489525
[5] -90552815925 -87397055925 -84241382325 -81085708725
[9] -77930035125 -74774275125 -71618601525 -68462927925
[13] -65307254325 -62151494325 -58995820725 -55840147125
[17] -52684473525 -49528713525 -46373039925 -43217366325
[21] -40061692725 -36905932725 -33750259125 -30594585525
[25] -27438911925 -24283151925 -21127478325 -17971804725
[29] -14816131125 -11660371125 -8504697525 -5349023925
[33] -2193350400 962406000 4118079600 7273753200
[37] 10429426800 13585186800 16740860400 19896534000
[41] 23052207600 26207967600 29363641200 32519314800
[45] 35674988400 38830748400 41986422000 45142095600
[49] 48297769200 51453529200 54609202800 57764876400
[53] 60920550000 64076310000 253418022000 3093543702000
[57] 31494800502000
> y <- .POSIXct(y)
> ## IGNORE_RDIFF_BEGIN
> (y1 <- strftime(y)) # leading zeros or spaces is platform-dependant
[1] "-1000000-07-01" "-100000-07-01" "-10000-07-01" "-1000-07-01"
[5] "-900-07-01" "-800-07-01" "-700-07-01" "-600-07-01"
[9] "-500-07-01" "-400-07-01" "-300-07-01" "-200-07-01"
[13] "-100-07-01" "0000-07-01" "0100-07-01" "0200-07-01"
[17] "0300-07-01" "0400-07-01" "0500-07-01" "0600-07-01"
[21] "0700-07-01" "0800-07-01" "0900-07-01" "1000-07-01"
[25] "1100-07-01" "1200-07-01" "1300-07-01" "1400-07-01"
[29] "1500-07-01" "1600-07-01" "1700-07-01" "1800-07-01"
[33] "1900-07-01" "2000-07-01" "2100-07-01" "2200-07-01"
[37] "2300-07-01" "2400-07-01" "2500-07-01" "2600-07-01"
[41] "2700-07-01" "2800-07-01" "2900-07-01" "3000-07-01"
[45] "3100-07-01" "3200-07-01" "3300-07-01" "3400-07-01"
[49] "3500-07-01" "3600-07-01" "3700-07-01" "3800-07-01"
[53] "3900-07-01" "4000-07-01" "10000-07-01" "100000-07-01"
[57] "1000000-07-01"
> ## IGNORE_RDIFF_END
> y2 <- strftime(y, "%_4Y-%m-%d") # not all platforms interpret this
> if(y2[1] != "4Y-07-01") print(y2) else message('format "%_4Y" unsupported')
[1] "-1000000-07-01" "-100000-07-01" "-10000-07-01" "-1000-07-01"
[5] "-900-07-01" "-800-07-01" "-700-07-01" "-600-07-01"
[9] "-500-07-01" "-400-07-01" "-300-07-01" "-200-07-01"
[13] "-100-07-01" " 0-07-01" " 100-07-01" " 200-07-01"
[17] " 300-07-01" " 400-07-01" " 500-07-01" " 600-07-01"
[21] " 700-07-01" " 800-07-01" " 900-07-01" "1000-07-01"
[25] "1100-07-01" "1200-07-01" "1300-07-01" "1400-07-01"
[29] "1500-07-01" "1600-07-01" "1700-07-01" "1800-07-01"
[33] "1900-07-01" "2000-07-01" "2100-07-01" "2200-07-01"
[37] "2300-07-01" "2400-07-01" "2500-07-01" "2600-07-01"
[41] "2700-07-01" "2800-07-01" "2900-07-01" "3000-07-01"
[45] "3100-07-01" "3200-07-01" "3300-07-01" "3400-07-01"
[49] "3500-07-01" "3600-07-01" "3700-07-01" "3800-07-01"
[53] "3900-07-01" "4000-07-01" "10000-07-01" "100000-07-01"
[57] "1000000-07-01"
>
> y <- double(length(years))
> for(i in seq_along(years)) {
+ zz$year = years[i] - 1900
+ zz$isdst <- -1
+ y[i] <- as.Date(zz)
+ }
> y
[1] -365961846 -37243596 -4371771 -1084589 -1048065 -1011540
[7] -975016 -938492 -901968 -865443 -828919 -792395
[13] -755871 -719346 -682822 -646298 -609774 -573249
[19] -536725 -500201 -463677 -427152 -390628 -354104
[25] -317580 -281055 -244531 -208007 -171483 -134958
[31] -98434 -61910 -25386 11139 47663 84187
[37] 120711 157236 193760 230284 266808 303333
[43] 339857 376381 412905 449430 485954 522478
[49] 559002 595527 632051 668575 705099 741624
[55] 2933079 35804904 364523154
> class(y) <- "Date"
> ## IGNORE_RDIFF_BEGIN
> (y3 <- strftime(y))
[1] "-1000000-07-01" "-100000-07-01" "-10000-07-01" "-1000-07-01"
[5] "-900-07-01" "-800-07-01" "-700-07-01" "-600-07-01"
[9] "-500-07-01" "-400-07-01" "-300-07-01" "-200-07-01"
[13] "-100-07-01" "0000-07-01" "0100-07-01" "0200-07-01"
[17] "0300-07-01" "0400-07-01" "0500-07-01" "0600-07-01"
[21] "0700-07-01" "0800-07-01" "0900-07-01" "1000-07-01"
[25] "1100-07-01" "1200-07-01" "1300-07-01" "1400-07-01"
[29] "1500-07-01" "1600-07-01" "1700-07-01" "1800-07-01"
[33] "1900-07-01" "2000-07-01" "2100-07-01" "2200-07-01"
[37] "2300-07-01" "2400-07-01" "2500-07-01" "2600-07-01"
[41] "2700-07-01" "2800-07-01" "2900-07-01" "3000-07-01"
[45] "3100-07-01" "3200-07-01" "3300-07-01" "3400-07-01"
[49] "3500-07-01" "3600-07-01" "3700-07-01" "3800-07-01"
[53] "3900-07-01" "4000-07-01" "10000-07-01" "100000-07-01"
[57] "1000000-07-01"
> ## IGNORE_RDIFF_END
> y4 <- strftime(y, "%_4Y-%m-%d")
> stopifnot(identical(y3, y1))
>
> zz <- as.POSIXlt("1900-07-01")
> years <- c(1800, 1847:1848, 1899:1902)
> y <- double(length(years))
> for(i in seq_along(years)) {
+ zz$year = years[i] - 1900
+ zz$isdst <- -1 # some are DST, some not so let the code decide
+ y[i] <- as.POSIXct(zz)
+ }
> print(y, digits=14)
[1] -5349023925 -3865881525 -3834259200 -2224886400 -2193350400 -2161814400
[7] -2130278400
> .POSIXct(y)
[1] "1800-07-01 LMT" "1847-07-01 LMT" "1848-07-01 GMT" "1899-07-01 GMT"
[5] "1900-07-01 GMT" "1901-07-01 GMT" "1902-07-01 GMT"
>
> ## change of 75s in 1847
> seq(as.POSIXlt("1847-11-24"), as.POSIXlt("1847-12-07"), by ="day")
[1] "1847-11-24 00:00:00 LMT" "1847-11-25 00:00:00 LMT"
[3] "1847-11-26 00:00:00 LMT" "1847-11-27 00:00:00 LMT"
[5] "1847-11-28 00:00:00 LMT" "1847-11-29 00:00:00 LMT"
[7] "1847-11-30 00:00:00 LMT" "1847-12-01 00:01:15 GMT"
[9] "1847-12-02 00:01:15 GMT" "1847-12-03 00:01:15 GMT"
[11] "1847-12-04 00:01:15 GMT" "1847-12-05 00:01:15 GMT"
[13] "1847-12-06 00:01:15 GMT"
>
> ## end of ------------- Tests of far-distant dates -----------
>
> ## Tests of %z and %Z for output.
> ## Use pf %z needs tm_gmtoff so offsets will otherwise be +0000
> x1 <- strptime("2022-07-01", "%Y-%m-%d", tz = "UTC")
> x2 <- strptime("2022-07-01", "%Y-%m-%d", tz = "Europe/Rome")
> x1
[1] "2022-07-01 UTC"
> x2
[1] "2022-07-01 CEST"
> # RFC5322 format
> format(x1, "%a, %d %b %Y %H:%M:%S %z")
[1] "Fri, 01 Jul 2022 00:00:00 +0000"
> # offset may not not determined: +0200 is correct
> format(x2, "%a, %d %b %Y %H:%M:%S %z")
[1] "Fri, 01 Jul 2022 00:00:00 +0200"
> format(as.POSIXct(x2), "%a, %d %b %Y %H:%M:%S %z") # usually correct
[1] "Fri, 01 Jul 2022 00:00:00 +0200"
> format(x1, "%a, %d %b %Y %H:%M:%S %Z")
[1] "Fri, 01 Jul 2022 00:00:00 UTC"
> format(x2, "%a, %d %b %Y %H:%M:%S %Z")
[1] "Fri, 01 Jul 2022 00:00:00 CEST"
>
> ## offsets not in whole hours:
> x3 <- strptime("2022-01-01", "%Y-%m-%d", tz = "Australia/Adelaide")
> format(as.POSIXct(x3), "%a, %d %b %Y %H:%M:%S %z") # +10h30m
[1] "Sat, 01 Jan 2022 00:00:00 +1030"
> # macOS' strftime prints the next two wrong.
> # Liberia does/did not have DST, so second abbreviation may be repeat or empty
> x4 <- strptime("1971-01-01", "%Y-%m-%d", tz = "Africa/Monrovia")
> y4 <- as.POSIXct(x4)
> str(unclass(as.POSIXlt(y4))) # correct gmtoff, printed wrong on macOS
List of 11
$ sec : num 0
$ min : int 0
$ hour : int 0
$ mday : int 1
$ mon : int 0
$ year : int 71
$ wday : int 5
$ yday : int 0
$ isdst : int 0
$ zone : chr "MMT"
$ gmtoff: int -2670
- attr(*, "tzone")= chr [1:3] "Africa/Monrovia" "GMT" " "
- attr(*, "balanced")= logi TRUE
> format(y4, "%a, %d %b %Y %H:%M:%S %z") # -44m, should be -00:44:30
[1] "Fri, 01 Jan 1971 00:00:00 -0044"
> ## timezones in 1900 might not be supported
> x5 <- strptime("1900-03-01", "%Y-%m-%d", tz = "Europe/Paris")
> y5 <- as.POSIXct(x5)
> str(unclass(as.POSIXlt(y5))) # ditto
List of 11
$ sec : num 0
$ min : int 0
$ hour : int 0
$ mday : int 1
$ mon : int 2
$ year : int 0
$ wday : int 4
$ yday : int 59
$ isdst : int 0
$ zone : chr "PMT"
$ gmtoff: int 561
- attr(*, "tzone")= chr [1:3] "Europe/Paris" "CET" "CEST"
- attr(*, "balanced")= logi TRUE
> format(y5, "%a, %d %b %Y %H:%M:%S %z")
[1] "Thu, 01 Mar 1900 00:00:00 +0009"
>