class: monash-bg-blue center middle hide-slide-number <div class="bg-black white" style="width:45%;right:0;bottom:0;padding-left:5px;border: solid 4px white;margin: auto;"> <i class="fas fa-exclamation-circle"></i> These slides are viewed best by Chrome and occasionally need to be refreshed if elements did not load properly. See here for <a href=day2-session3.pdf>PDF <i class="fas fa-file-pdf"></i></a>. </div> <br> .white[Press the **right arrow** to progress to the next slide!] --- count: false background-image: url(images/bg1.jpg) background-size: cover class: hide-slide-number title-slide <div class="grid-row" style="grid: 1fr / 2fr;"> .item.center[ # <span style="text-shadow: 2px 2px 30px white;">Data Wrangling with R: Day 2</span> <!-- ## <span style="color:;text-shadow: 2px 2px 30px black;">Dealing with dates with `lubridate`</span> --> ] .center.shade_black.animated.bounceInUp.slower[ <br><br> ## <span style="color: #ccf2ff; text-shadow: 10px 10px 100px white;">Dealing with dates with `lubridate`</span> <br> Presented by Emi Tanaka Department of Econometrics and Business Statistics <img src="images/monash-one-line-reversed.png" style="width:500px"><br> <span><i class="fas fa-envelope faa-float animated "></i></span> emi.tanaka@monash.edu <span><i class="fab fa-twitter faa-float animated faa-fast "></i></span> @statsgen .bottom_abs.width100.bg-black[ 2nd December 2020 @ Statistical Society of Australia | Zoom ] ] </div> --- # Date in R .font_small[Base R .font_small[Part ]1] * Dealing with dates alone is relatively straightforward .font_small[compared to date and time] -- * Dealing with date _and_ time is ... -- tricky -- so let's start with dates -- ```r Sys.Date() # System Date, gets the date when the command is run ``` ``` ## [1] "2020-12-03" ``` -- * Dates in R have class .monash-blue[**`Date`**] 📅 even though it looks like `character` 🔢 ```r class(Sys.Date()) ``` ``` ## [1] "Date" ``` -- * It's actually a numerical value under the hood{{content}} ```r unclass(Sys.Date()) ``` ``` ## [1] 18599 ``` -- , what is this number? 🤔 --- # Date in R .font_small[Base R .font_small[Part ]2] * <i class="fas fa-info-circle"></i> **1st January 1970** is a special reference point -- * Let's have a look at the numerical value under the hood of `Date` objects -- ```r unclass(as.Date("1970/01/02")) ``` ``` ## [1] 1 ``` -- ```r unclass(as.Date("1969/12/31")) ``` ``` ## [1] -1 ``` -- * Yup, the number under the hood is the number of days after (if positive) or before (if negative) 1st January 1970 -- * And yes, you can use `as.Date` to convert objects to `Date` <i class="fas fa-calendar"></i> --- # Date in R .font_small[Base R .font_small[Part ]3] * Dates do no have to be in the format of "YYYY/MM/DD" .font_small[(in fact, there are many format in the wild)] -- * If it has a different format, then you can use the conversion specification with a "%" symbol followed by a single letter .font_small[note quite regex, but like it] ```r as.Date("Xmas is 25 December 2020", format = "Xmas is %d %B %Y") ``` ``` ## [1] "2020-12-25" ``` -- * You can find some widely used conversion specification in documentation at<br> `?strptime` but some _depends on your operating system_ * Below are some common ones: .grid[ .item[ * `%b` abbreviated month * `%B` full month ] .item[ * `%e` day of the month (01, 02, ..., 31) * `%d` day of the month (1, 2, ..., 31) ] .item[ * `%y` year without century (00-99) * `%Y` year with century, e.g. 1999 ] ] --- # <img src="images/no-toilet-roll.png" height = "40px"> System locale * "aralık" is December in Turkey ```r as.Date("Xmas is 25 aralık 2020", format = "Xmas is %d %B %Y") ``` ``` ## [1] NA ``` -- * Let's temorary set our system locale to Turkey ```r Sys.setlocale("LC_TIME", "tr_TR.UTF-8") # temporary set to Turkey locale ``` ```r as.Date("Xmas is 25 aralık 2020", format = "Xmas is %d %B %Y") ``` -- ``` ## [1] "2020-12-25" ``` -- (And set it back to English again) .font_small["UTF-8" might only for Unix and Linux systems] ```r Sys.setlocale("LC_TIME", "en_AU.UTF-8") ``` --- # Date and Time in R .font_small[Base R .font_small[Part ]1] * two main date-time classes in R: .monash-blue[**`POSIXct`**] and .monash-blue[**`POSIXlt`**] .font_small[avoid using `POSIXlt` if possible] -- * POSIX stands for Portable Operating System Interface * `ct` stands for calendar time ```r as.POSIXct("2020-12-02 13:00", format = "%Y-%m-%e %H:%M") ``` ``` ## [1] "2020-12-02 13:00:00 AEDT" ``` -- ```r unclass(as.POSIXct("2020-12-02 13:00", format = "%Y-%m-%e %H:%M")) ``` ``` ## [1] 1606874400 ## attr(,"tzone") ## [1] "" ``` -- * <i class="fas fa-info-circle"></i> **1970/01/01 00:00:00 UTC** is a special reference point called **_Unix epoch_** and the above number is the number of seconds after Unix epoch --- # Date and Time in R .font_small[Base R .font_small[Part ]2] * `POSIXlt` seems like it's the same as `POSIXct` ```r as.POSIXlt("2020-12-02 13:00", format = "%Y-%m-%e %H:%M") ``` ``` ## [1] "2020-12-02 13:00:00 AEDT" ``` -- * But under the hood, it's a list of time attributes ```r unclass(as.POSIXlt("2020-12-02 13:00", format = "%Y-%m-%e %H:%M")) ``` ``` ## $sec ## [1] 0 ## ## $min ## [1] 0 ## ## $hour ## [1] 13 ## ## $mday ## [1] 2 ## ## $mon ## [1] 11 ## ## $year ## [1] 120 ## ## $wday ## [1] 3 ## ## $yday ## [1] 336 ## ## $isdst ## [1] 1 ## ## $zone ## [1] "AEDT" ## ## $gmtoff ## [1] NA ``` --- # Time zone ```r melb <- as.POSIXct("2020-12-02 13:00", format = "%Y-%m-%e %H:%M", * tz = "Australia/Melbourne") perth <- as.POSIXct("2020-12-02 13:00", format = "%Y-%m-%e %H:%M", * tz = "Australia/Perth") melb - perth ``` ``` ## Time difference of -3 hours ``` -- * You can find the names of the time zones using .monash-blue[**`OlsonNames()`**] -- * If you want to know which time zone your system is using: ```r Sys.timezone() ``` ``` ## [1] "Australia/Melbourne" ``` --- class: transition middle # Working with `lubridate` --- # Date in R .font_small[`lubridate`] * Remember, `lubridate` isn't part of core `tidyverse` so you have to load it up explicitly ```r library(lubridate) ``` -- * To convert string to a `Date`, you can use `ymd` and friends. E.g. ```r ymd("2012 Dec 30th") ``` ``` ## [1] "2012-12-30" ``` -- ```r mdy("01/30 99") ``` ``` ## [1] "1999-01-30" ``` -- ```r dmy("1st January 2015") ``` ``` ## [1] "2015-01-01" ``` -- <div class="info-box pad20" style="position:absolute;right:10px;bottom:10px;width:480px;"> You might have guessed it but:<br> <code>y</code> = year, <code>m</code> = month, and <code>d</code> = day. <br><br> The order determines the expected order of its appearance in the string </div> --- # Date and time in R .font_small[`lubridate`] * To convert string to `POSIXct`, you can use `ymd_hms` and friends -- ```r ymd_hms("20140101 201001", tz = "Australia/Melbourne") ``` ``` ## [1] "2014-01-01 20:10:01 AEDT" ``` -- ```r mdy_h("09/09/2010 4PM") ``` ``` ## [1] "2010-09-09 16:00:00 UTC" ``` -- ```r ydm_hm("Today is not 2009 9th Sep 4:30PM") ``` ``` ## [1] "2009-09-09 16:30:00 UTC" ``` -- ```r ydm_hms("19 9 July | 4:30:03.34343") ``` ``` ## [1] "2019-07-09 04:30:03 UTC" ``` -- <div class="info-box pad20" style="position:absolute;right:10px;bottom:10px;width:480px;margin-right:10px;"> <code>h</code> = hour, <code>m</code> = minute, and <br><code>s</code> = second. <br><br> It's remarkably clever! <br><br> The time has to be after date though. </div> --- # Conversion to date and time .font_small[`lubridate`] Making `Date` from individual date components: ```r make_date(year = 2018, month = 8, day = 3) ``` ``` ## [1] "2018-08-03" ``` Making `POSIXct` from individual components: ```r make_datetime(year = 2018, month = 8, day = 3, hour = 10, min = 3, sec = 30) ``` ``` ## [1] "2018-08-03 10:03:30 UTC" ``` --- # Extracting date or time components .font_small[`lubridate`] ```r t1 <- ymd_hms("20101010 13:30:30") ``` ```r month(t1, label = TRUE) ``` ``` ## [1] Oct ## 12 Levels: Jan < Feb < Mar < Apr < May < Jun < Jul < Aug < Sep < ... < Dec ``` .grid[ .item[ ```r year(t1) ``` ``` ## [1] 2010 ``` ```r month(t1) ``` ``` ## [1] 10 ``` ```r day(t1) ``` ``` ## [1] 10 ``` ] .item[ ```r hour(t1) ``` ``` ## [1] 13 ``` ```r minute(t1) ``` ``` ## [1] 30 ``` ```r second(t1) ``` ``` ## [1] 30 ``` ] .item[ ```r yday(t1) ``` ``` ## [1] 283 ``` ```r mday(t1) ``` ``` ## [1] 10 ``` ```r wday(t1) ``` ``` ## [1] 1 ``` ] ] --- # Date and time modifiers ```r month(t1) <- 3 t1 ``` ``` ## [1] "2010-03-10 13:30:30 UTC" ``` ```r mday(t1) <- 20 t1 ``` ``` ## [1] "2010-03-20 13:30:30 UTC" ``` ```r with_tz(t1, "Australia/Perth") ``` ``` ## [1] "2010-03-20 21:30:30 AWST" ``` --- # Durations .font_small[`lubridate`] * `Duration` is a special class in `lubridate` * Some convenient constructors for `Duration` are: ```r dyears(1) ``` ``` ## [1] "31557600s (~1 years)" ``` ```r dweeks(10) ``` ``` ## [1] "6048000s (~10 weeks)" ``` ```r ddays(4) ``` ``` ## [1] "345600s (~4 days)" ``` ```r dhours(3) ``` ``` ## [1] "10800s (~3 hours)" ``` --- # Maths with Durations .font_small[`lubridate`] ```r ddays(4) + dweeks(1) ``` ``` ## [1] "950400s (~1.57 weeks)" ``` ```r ymd("2013-01-01") + ddays(5) ``` ``` ## [1] "2013-01-06" ``` ```r ymd_hms("2020-10-1 2:00:00", tz = "Australia/Melbourne") + ddays(1) ``` ``` ## [1] "2020-10-02 02:00:00 AEST" ``` -- * What happened below? ```r ymd_hms("2020-10-4 1:00:00", tz = "Australia/Melbourne") + dhours(1) ``` ``` ## [1] "2020-10-04 03:00:00 AEDT" ``` -- * Day light saving started at Sun 4th Oct 2020 2AM in Melbourne --- # Period .font_small[`lubridate`] * `Period` is a special class in `lubridate` * Constructors for `Period` are like for `Duration` but without the prefix "d": ```r years(1) ``` ``` ## [1] "1y 0m 0d 0H 0M 0S" ``` ```r weeks(10) ``` ``` ## [1] "70d 0H 0M 0S" ``` ```r days(4) ``` ``` ## [1] "4d 0H 0M 0S" ``` ```r hours(3) ``` ``` ## [1] "3H 0M 0S" ``` --- # Maths with Period .font_small[`lubridate`] ```r days(4) + weeks(1) ``` ``` ## [1] "11d 0H 0M 0S" ``` ```r ymd("2013-01-01") + days(5) ``` ``` ## [1] "2013-01-06" ``` ```r ymd_hms("2020-10-1 2:00:00", tz = "Australia/Melbourne") + days(1) ``` ``` ## [1] "2020-10-02 02:00:00 AEST" ``` -- ```r ymd_hms("2020-10-4 1:00:00", tz = "Australia/Melbourne") + hours(1) ``` ``` ## [1] NA ``` -- ```r ymd_hms("2020-10-4 1:00:00", tz = "Australia/Melbourne") + hours(2) ``` ``` ## [1] "2020-10-04 03:00:00 AEDT" ``` --- class: exercise middle hide-slide-number # <i class="fas fa-code"></i> If you installed the `dwexercise` package, <br> run below in your R console ```r learnr::run_tutorial("day2-exercise-03", package = "dwexercise") ``` <br> # <i class="fas fa-link"></i> If the above doesn't work for you, go [here](https://ebsmonash.shinyapps.io/dw-day2-exercise-03). # <i class="fas fa-question"></i> Questions or issues, let us know! <center> <div class="countdown clock" id="timer_5fc873b6" style="right:0;bottom:0;" data-warnwhen="0"> <code class="countdown-time"><span class="countdown-digits minutes">15</span><span class="countdown-digits colon">:</span><span class="countdown-digits seconds">00</span></code> </div> </center> --- class: font_smaller background-color: #e5e5e5 # Session Information .scroll-350[ ```r devtools::session_info() ``` ``` ## ─ Session info ─────────────────────────────────────────────────────────────── ## setting value ## version R version 4.0.1 (2020-06-06) ## os macOS Catalina 10.15.7 ## system x86_64, darwin17.0 ## ui X11 ## language (EN) ## collate en_AU.UTF-8 ## ctype en_AU.UTF-8 ## tz Australia/Melbourne ## date 2020-12-03 ## ## ─ Packages ─────────────────────────────────────────────────────────────────── ## package * version date lib source ## anicon 0.1.0 2020-06-21 [1] Github (emitanaka/anicon@0b756df) ## assertthat 0.2.1 2019-03-21 [2] CRAN (R 4.0.0) ## backports 1.2.0 2020-11-02 [1] CRAN (R 4.0.2) ## broom 0.7.2 2020-10-20 [1] CRAN (R 4.0.2) ## callr 3.5.1 2020-10-13 [1] CRAN (R 4.0.2) ## cellranger 1.1.0 2016-07-27 [2] CRAN (R 4.0.0) ## cli 2.2.0 2020-11-20 [1] CRAN (R 4.0.1) ## colorspace 2.0-0 2020-11-11 [1] CRAN (R 4.0.2) ## countdown 0.3.5 2020-07-20 [1] Github (gadenbuie/countdown@a544fa4) ## crayon 1.3.4 2017-09-16 [2] CRAN (R 4.0.0) ## DBI 1.1.0 2019-12-15 [1] CRAN (R 4.0.2) ## dbplyr 2.0.0 2020-11-03 [1] CRAN (R 4.0.2) ## desc 1.2.0 2018-05-01 [2] CRAN (R 4.0.0) ## devtools 2.3.2 2020-09-18 [1] CRAN (R 4.0.2) ## digest 0.6.27 2020-10-24 [1] CRAN (R 4.0.2) ## dplyr * 1.0.2 2020-08-18 [1] CRAN (R 4.0.2) ## ellipsis 0.3.1 2020-05-15 [2] CRAN (R 4.0.0) ## evaluate 0.14 2019-05-28 [2] CRAN (R 4.0.0) ## fansi 0.4.1 2020-01-08 [2] CRAN (R 4.0.0) ## forcats * 0.5.0 2020-03-01 [2] CRAN (R 4.0.0) ## fs 1.5.0 2020-07-31 [1] CRAN (R 4.0.2) ## generics 0.1.0 2020-10-31 [2] CRAN (R 4.0.2) ## ggplot2 * 3.3.2 2020-06-19 [1] CRAN (R 4.0.2) ## glue 1.4.2 2020-08-27 [1] CRAN (R 4.0.2) ## gtable 0.3.0 2019-03-25 [2] CRAN (R 4.0.0) ## haven 2.3.1 2020-06-01 [2] CRAN (R 4.0.0) ## hms 0.5.3 2020-01-08 [2] CRAN (R 4.0.0) ## htmltools 0.5.0 2020-06-16 [1] CRAN (R 4.0.2) ## httr 1.4.2 2020-07-20 [1] CRAN (R 4.0.2) ## icon 0.1.0 2020-06-21 [1] Github (emitanaka/icon@8458546) ## jsonlite 1.7.1 2020-09-07 [1] CRAN (R 4.0.2) ## knitr 1.30 2020-09-22 [1] CRAN (R 4.0.2) ## lifecycle 0.2.0 2020-03-06 [1] CRAN (R 4.0.0) ## lubridate * 1.7.9 2020-06-08 [2] CRAN (R 4.0.1) ## magrittr 2.0.1 2020-11-17 [1] CRAN (R 4.0.2) ## memoise 1.1.0 2017-04-21 [2] CRAN (R 4.0.0) ## modelr 0.1.8 2020-05-19 [2] CRAN (R 4.0.0) ## munsell 0.5.0 2018-06-12 [2] CRAN (R 4.0.0) ## pillar 1.4.7 2020-11-20 [1] CRAN (R 4.0.1) ## pkgbuild 1.1.0 2020-07-13 [2] CRAN (R 4.0.1) ## pkgconfig 2.0.3 2019-09-22 [2] CRAN (R 4.0.0) ## pkgload 1.1.0 2020-05-29 [2] CRAN (R 4.0.0) ## prettyunits 1.1.1 2020-01-24 [2] CRAN (R 4.0.0) ## processx 3.4.4 2020-09-03 [1] CRAN (R 4.0.2) ## ps 1.4.0 2020-10-07 [1] CRAN (R 4.0.2) ## purrr * 0.3.4 2020-04-17 [2] CRAN (R 4.0.0) ## R6 2.5.0 2020-10-28 [1] CRAN (R 4.0.2) ## Rcpp 1.0.5 2020-07-06 [1] CRAN (R 4.0.0) ## readr * 1.4.0 2020-10-05 [2] CRAN (R 4.0.2) ## readxl 1.3.1 2019-03-13 [2] CRAN (R 4.0.0) ## remotes 2.2.0 2020-07-21 [1] CRAN (R 4.0.2) ## reprex 0.3.0.9001 2020-08-08 [1] Github (tidyverse/reprex@9594ee9) ## rlang 0.4.8 2020-10-08 [1] CRAN (R 4.0.2) ## rmarkdown 2.5 2020-10-21 [1] CRAN (R 4.0.1) ## rprojroot 2.0.2 2020-11-15 [1] CRAN (R 4.0.2) ## rstudioapi 0.13 2020-11-12 [1] CRAN (R 4.0.1) ## rvest 0.3.6 2020-07-25 [1] CRAN (R 4.0.2) ## scales 1.1.1 2020-05-11 [2] CRAN (R 4.0.0) ## sessioninfo 1.1.1 2018-11-05 [2] CRAN (R 4.0.0) ## stringi 1.5.3 2020-09-09 [2] CRAN (R 4.0.2) ## stringr * 1.4.0 2019-02-10 [2] CRAN (R 4.0.0) ## testthat 3.0.0 2020-10-31 [1] CRAN (R 4.0.2) ## tibble * 3.0.4.9000 2020-11-26 [1] Github (tidyverse/tibble@9eeef4d) ## tidyr * 1.1.2 2020-08-27 [1] CRAN (R 4.0.2) ## tidyselect 1.1.0 2020-05-11 [2] CRAN (R 4.0.0) ## tidyverse * 1.3.0 2019-11-21 [1] CRAN (R 4.0.2) ## usethis 1.6.3 2020-09-17 [1] CRAN (R 4.0.2) ## vctrs 0.3.5.9000 2020-11-26 [1] Github (r-lib/vctrs@957baf7) ## whisker 0.4 2019-08-28 [2] CRAN (R 4.0.0) ## withr 2.3.0 2020-09-22 [1] CRAN (R 4.0.2) ## xaringan 0.18 2020-10-21 [1] CRAN (R 4.0.2) ## xfun 0.19 2020-10-30 [1] CRAN (R 4.0.2) ## xml2 1.3.2 2020-04-23 [2] CRAN (R 4.0.0) ## yaml 2.2.1 2020-02-01 [1] CRAN (R 4.0.2) ## ## [1] /Users/etan0038/Library/R/4.0/library ## [2] /Library/Frameworks/R.framework/Versions/4.0/Resources/library ``` ] These slides are licensed under <br><center><a href="https://creativecommons.org/licenses/by-sa/3.0/au/"><img src="images/cc.svg" style="height:2em;"/><img src="images/by.svg" style="height:2em;"/><img src="images/sa.svg" style="height:2em;"/></a></center>