blog/groundhog-day.html

<!DOCTYPE html>     <html class="no-js"> <head> <meta charset='utf-8'/><meta http-equiv='X-UA-Compatible' content='IE=edge'/><meta name='viewport' content='width=device-width, initial-scale=1'/><meta name='keywords' content='groovy, datetime, timecategory, date'/><meta name='description' content='Inspired by a recent tweet, this blog looks at some datetime manipulations to calculate the period between Groundhog day and the start of Spring.'/><title>The Apache Groovy programming language - Blogs - Groundhog Day</title><link href='../img/favicon.ico' type='image/x-ico' rel='icon'/><script src='../js/matomo.js'></script><link rel='stylesheet' type='text/css' href='../css/bootstrap.css'/><link rel='stylesheet' type='text/css' href='../css/font-awesome.min.css'/><link rel='stylesheet' type='text/css' href='../css/style.css'/><link rel='stylesheet' type='text/css' href='../css/../css/prettify.min.css'/> </head><body> <div id='fork-me'> <a href='https://github.com/apache/groovy'> <img style='position: fixed; 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background-color: #eee'><span>Related posts</span></li><li><a href='./australian-timezones'>Australian Time Zones</a></li><li><a href='./groovy-dates-and-times-cheat'>Groovy™ Dates And Times Cheat Sheet</a></li></ul></div><div class='col-lg-8 col-lg-pull-0'><a name='doc'></a><h1>Groundhog Day</h1><p><div style='display:flex;padding:0.2ex'><span>Author: </span><i>Paul King</i></div><br/><span>Published: 2023-02-02 12:00AM</span></p><hr/><div class="paragraph"> <p><a href="https://twitter.com/kenkousen">Ken Kousen</a> posted a <a href="https://twitter.com/kenkousen/status/1621272529481367554">tweet</a> in honor of <a href="https://en.wikipedia.org/wiki/Groundhog_Day">Groundhog Day</a> looking at the kotlinx-datetime library.</p> </div> <div class="paragraph"> <p><span class="image"><img src="img/Groundhog.png" alt="Groundhog"></span></p> </div> <div class="paragraph"> <p>The North American tradition, or superstition, depending on how you view such things, is that if the Groundhog emerges from its burrow and sees its shadow, Winter will continue for 6 weeks, but otherwise Spring will come early.</p> </div> <div class="paragraph"> <p>Looking at the dates for 2023 (it differs slightly each year) we can see that Spring isn’t due for 6 weeks and 4 days, so if Spring starts in 6 weeks, it is early anyway! While it certainly falls into the category of nerds having fun, it’s a good simple example of using date library functionality.</p> </div> <div class="paragraph"> <p>This blog looks at a similar Groovy solution:</p> </div> <div class="listingblock"> <div class="content"> <pre class="prettyprint highlight"><code data-lang="groovy">var groundHogDay = LocalDate.of(2023, FEBRUARY, 2) var springEquinoxNorthernHemisphere = LocalDate.of(2023, MARCH, 20) var expectedDays = use(TimeCategory) { 6.weeks + 4.days }.days assert springEquinoxNorthernHemisphere - groundHogDay == expectedDays</code></pre> </div> </div></div></div></div></div><footer id='footer'> <div class='row'> <div class='colset-3-footer'> <div class='col-1'> <h1>Groovy</h1><ul> <li><a href='https://groovy-lang.org/learn.html'>Learn</a></li><li><a href='https://groovy-lang.org/documentation.html'>Documentation</a></li><li><a href='/download.html'>Download</a></li><li><a href='https://groovy-lang.org/support.html'>Support</a></li><li><a href='/'>Contribute</a></li><li><a href='https://groovy-lang.org/ecosystem.html'>Ecosystem</a></li><li><a href='/blog'>Blog posts</a></li><li><a href='https://groovy.apache.org/events.html'></a></li> </ul> </div><div class='col-2'> <h1>About</h1><ul> <li><a href='https://github.com/apache/groovy'>Source code</a></li><li><a href='https://groovy-lang.org/security.html'>Security</a></li><li><a href='https://groovy-lang.org/learn.html#books'>Books</a></li><li><a href='https://groovy-lang.org/thanks.html'>Thanks</a></li><li><a href='http://www.apache.org/foundation/sponsorship.html'>Sponsorship</a></li><li><a href='https://groovy-lang.org/faq.html'>FAQ</a></li><li><a href='https://groovy-lang.org/search.html'>Search</a></li> </ul> </div><div class='col-3'> <h1>Socialize</h1><ul> <li><a href='https://groovy-lang.org/mailing-lists.html'>Discuss on the mailing-list</a></li><li><a href='https://twitter.com/ApacheGroovy'>Groovy on Twitter</a></li><li><a href='https://groovy-lang.org/events.html'>Events and conferences</a></li><li><a href='https://github.com/apache/groovy'>Source code on GitHub</a></li><li><a href='https://groovy-lang.org/reporting-issues.html'>Report issues in Jira</a></li><li><a href='http://stackoverflow.com/questions/tagged/groovy'>Stack Overflow questions</a></li><li><a href='http://www.groovycommunity.com/'>Slack Community</a></li> </ul> </div><div class='col-right'> <p> The Groovy programming language is supported by the <a href='http://www.apache.org'>Apache Software Foundation</a> and the Groovy community. </p><div text-align='right'> <img src='../img/asf_logo.png' title='The Apache Software Foundation' alt='The Apache Software Foundation' style='width:60%'/> </div><p>Apache, Apache Groovy, Groovy, and the Apache feather logo are either registered trademarks or trademarks of The Apache Software Foundation.</p> </div> </div><div class='clearfix'>© 2003-2025 the Apache Groovy project — Groovy is Open Source: <a href='http://www.apache.org/licenses/LICENSE-2.0.html' alt='Apache 2 License'>license</a>, <a href='https://privacy.apache.org/policies/privacy-policy-public.html'>privacy policy</a>.</div> </div> </footer></div> </div> </div> </div> </div><script src='../js/vendor/jquery-1.10.2.min.js' defer></script><script src='../js/vendor/classie.js' defer></script><script src='../js/vendor/bootstrap.js' defer></script><script src='../js/vendor/sidebarEffects.js' defer></script><script src='../js/vendor/modernizr-2.6.2.min.js' defer></script><script src='../js/plugins.js' defer></script><script src='../js/vendor/prettify.min.js'></script><script>document.addEventListener('DOMContentLoaded',prettyPrint)</script> </body></html>

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