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<title>Go by Example: Time</title>
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<div class="example" id="time">
<h2><a href="./">Go by Example</a>: Time</h2>
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<p>Go&rsquo;s offers extensive support for times and durations;
here are some examples.</p>
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<a href="http://play.golang.org/p/NxuQTlVA2l"><img title="Run code" src="play.png" class="run" /></a>
<div class="highlight"><pre><span class="kn">package</span> <span class="nx">main</span>
</pre></div>
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<div class="highlight"><pre><span class="kn">import</span> <span class="s">&quot;fmt&quot;</span>
<span class="kn">import</span> <span class="s">&quot;time&quot;</span>
</pre></div>
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<div class="highlight"><pre><span class="kd">func</span> <span class="nx">main</span><span class="p">()</span> <span class="p">{</span>
<span class="nx">p</span> <span class="o">:=</span> <span class="nx">fmt</span><span class="p">.</span><span class="nx">Println</span>
</pre></div>
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<p>We&rsquo;ll start by getting the current time.</p>
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<div class="highlight"><pre> <span class="nx">now</span> <span class="o">:=</span> <span class="nx">time</span><span class="p">.</span><span class="nx">Now</span><span class="p">()</span>
<span class="nx">p</span><span class="p">(</span><span class="nx">now</span><span class="p">)</span>
</pre></div>
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<p>You can build a <code>time</code> struct by providing the
year, month, day, etc. Times are always associated
with a <code>Location</code>, i.e. time zone.</p>
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<div class="highlight"><pre> <span class="nx">then</span> <span class="o">:=</span> <span class="nx">time</span><span class="p">.</span><span class="nx">Date</span><span class="p">(</span>
<span class="mi">2009</span><span class="p">,</span> <span class="mi">11</span><span class="p">,</span> <span class="mi">17</span><span class="p">,</span> <span class="mi">20</span><span class="p">,</span> <span class="mi">34</span><span class="p">,</span> <span class="mi">58</span><span class="p">,</span> <span class="mi">651387237</span><span class="p">,</span> <span class="nx">time</span><span class="p">.</span><span class="nx">UTC</span><span class="p">)</span>
<span class="nx">p</span><span class="p">(</span><span class="nx">then</span><span class="p">)</span>
</pre></div>
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<p>You can extract the various components of the time
value as expected.</p>
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<div class="highlight"><pre> <span class="nx">p</span><span class="p">(</span><span class="nx">then</span><span class="p">.</span><span class="nx">Year</span><span class="p">())</span>
<span class="nx">p</span><span class="p">(</span><span class="nx">then</span><span class="p">.</span><span class="nx">Month</span><span class="p">())</span>
<span class="nx">p</span><span class="p">(</span><span class="nx">then</span><span class="p">.</span><span class="nx">Day</span><span class="p">())</span>
<span class="nx">p</span><span class="p">(</span><span class="nx">then</span><span class="p">.</span><span class="nx">Hour</span><span class="p">())</span>
<span class="nx">p</span><span class="p">(</span><span class="nx">then</span><span class="p">.</span><span class="nx">Minute</span><span class="p">())</span>
<span class="nx">p</span><span class="p">(</span><span class="nx">then</span><span class="p">.</span><span class="nx">Second</span><span class="p">())</span>
<span class="nx">p</span><span class="p">(</span><span class="nx">then</span><span class="p">.</span><span class="nx">Nanosecond</span><span class="p">())</span>
<span class="nx">p</span><span class="p">(</span><span class="nx">then</span><span class="p">.</span><span class="nx">Location</span><span class="p">())</span>
</pre></div>
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<p>The Monday-Sunday <code>Weekday</code> is also available.</p>
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<div class="highlight"><pre> <span class="nx">p</span><span class="p">(</span><span class="nx">then</span><span class="p">.</span><span class="nx">Weekday</span><span class="p">())</span>
</pre></div>
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<p>These methods compare two times, testing if the
first occurs before, after, or at the same time
as the second, respectively.</p>
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<div class="highlight"><pre> <span class="nx">p</span><span class="p">(</span><span class="nx">then</span><span class="p">.</span><span class="nx">Before</span><span class="p">(</span><span class="nx">now</span><span class="p">))</span>
<span class="nx">p</span><span class="p">(</span><span class="nx">then</span><span class="p">.</span><span class="nx">After</span><span class="p">(</span><span class="nx">now</span><span class="p">))</span>
<span class="nx">p</span><span class="p">(</span><span class="nx">then</span><span class="p">.</span><span class="nx">Equal</span><span class="p">(</span><span class="nx">now</span><span class="p">))</span>
</pre></div>
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<p>The <code>Sub</code> methods returns a <code>Duration</code> representing
the interval between two times.</p>
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<div class="highlight"><pre> <span class="nx">diff</span> <span class="o">:=</span> <span class="nx">now</span><span class="p">.</span><span class="nx">Sub</span><span class="p">(</span><span class="nx">then</span><span class="p">)</span>
<span class="nx">p</span><span class="p">(</span><span class="nx">diff</span><span class="p">)</span>
</pre></div>
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<p>We can compute the length of the duration in
various units.</p>
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<div class="highlight"><pre> <span class="nx">p</span><span class="p">(</span><span class="nx">diff</span><span class="p">.</span><span class="nx">Hours</span><span class="p">())</span>
<span class="nx">p</span><span class="p">(</span><span class="nx">diff</span><span class="p">.</span><span class="nx">Minutes</span><span class="p">())</span>
<span class="nx">p</span><span class="p">(</span><span class="nx">diff</span><span class="p">.</span><span class="nx">Seconds</span><span class="p">())</span>
<span class="nx">p</span><span class="p">(</span><span class="nx">diff</span><span class="p">.</span><span class="nx">Nanoseconds</span><span class="p">())</span>
</pre></div>
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<p>You can use <code>Add</code> to advance a time by a given
duration, or with a <code>-</code> to move backwards by a
duration.</p>
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<div class="highlight"><pre> <span class="nx">p</span><span class="p">(</span><span class="nx">then</span><span class="p">.</span><span class="nx">Add</span><span class="p">(</span><span class="nx">diff</span><span class="p">))</span>
<span class="nx">p</span><span class="p">(</span><span class="nx">then</span><span class="p">.</span><span class="nx">Add</span><span class="p">(</span><span class="o">-</span><span class="nx">diff</span><span class="p">))</span>
<span class="p">}</span>
</pre></div>
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<div class="highlight"><pre><span class="gp">$</span> go run time.go
<span class="go">2012-10-31 15:50:13.793654 +0000 UTC</span>
<span class="go">2009-11-17 20:34:58.651387237 +0000 UTC</span>
<span class="go">2009</span>
<span class="go">November</span>
<span class="go">17</span>
<span class="go">20</span>
<span class="go">34</span>
<span class="go">58</span>
<span class="go">651387237</span>
<span class="go">UTC</span>
<span class="go">Tuesday</span>
<span class="go">true</span>
<span class="go">false</span>
<span class="go">false</span>
<span class="go">25891h15m15.142266763s</span>
<span class="go">25891.25420618521</span>
<span class="go">1.5534752523711128e+06</span>
<span class="go">9.320851514226677e+07</span>
<span class="go">93208515142266763</span>
<span class="go">2012-10-31 15:50:13.793654 +0000 UTC</span>
<span class="go">2006-12-05 01:19:43.509120474 +0000 UTC</span>
</pre></div>
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<p>Next we&rsquo;ll look at the related idea of time relative to
the Unix epoch.</p>
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<p class="next">
Next example: <a href="epoch">Epoch</a>.
</p>
<p class="footer">
by <a href="https://twitter.com/mmcgrana">@mmcgrana</a> | <a href="mailto:mmcgrana@gmail.com">feedback</a> | <a href="https://github.com/mmcgrana/gobyexample/blob/master/examples/time">source</a> | <a href="https://github.com/mmcgrana/gobyexample#license">license</a>
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