176 lines
6.5 KiB
Plaintext
176 lines
6.5 KiB
Plaintext
<!DOCTYPE html>
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<html>
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<head>
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<meta http-eqiv="content-type" content="text/html;charset=utf-8">
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<title>Go by Example: Epoch</title>
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<div class="example" id="epoch">
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<h2><a href="./">Go by Example</a>: Epoch</h2>
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<table>
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<tr>
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<td class="docs">
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<p>A common requirement in programs is getting the number
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of seconds, milliseconds, or nanoseconds since the
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<a href="http://en.wikipedia.org/wiki/Unix_time">Unix epoch</a>.
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Here’s how to do it in Go.</p>
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</td>
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<td class="code empty leading">
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</td>
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</tr>
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<tr>
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<td class="docs">
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</td>
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<td class="code leading">
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<a href="http://play.golang.org/p/GP_zEjhlWk"><img title="Run code" src="play.png" class="run" /></a>
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<div class="highlight"><pre><span class="kn">package</span> <span class="nx">main</span>
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</pre></div>
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</td>
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</tr>
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<tr>
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<td class="docs">
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</td>
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<td class="code leading">
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<div class="highlight"><pre><span class="kn">import</span> <span class="s">"fmt"</span>
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<span class="kn">import</span> <span class="s">"time"</span>
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</pre></div>
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</td>
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</tr>
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<tr>
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<td class="docs">
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</td>
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<td class="code leading">
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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>
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</pre></div>
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</td>
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</tr>
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<tr>
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<td class="docs">
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<p>Use <code>time.Now</code> with <code>Unix</code> or <code>UnixNano</code> to get
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elapsed time since the Unix epoch in seconds or
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nanoseconds, respectively.</p>
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</td>
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<td class="code leading">
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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>
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<span class="nx">secs</span> <span class="o">:=</span> <span class="nx">now</span><span class="p">.</span><span class="nx">Unix</span><span class="p">()</span>
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<span class="nx">nanos</span> <span class="o">:=</span> <span class="nx">now</span><span class="p">.</span><span class="nx">UnixNano</span><span class="p">()</span>
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<span class="nx">fmt</span><span class="p">.</span><span class="nx">Println</span><span class="p">(</span><span class="nx">now</span><span class="p">)</span>
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</pre></div>
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</td>
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</tr>
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<tr>
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<td class="docs">
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<p>Note that there is no <code>UnixMillis</code>, so to get the
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milliseconds since epoch you’ll need to manually
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divide from nanoseconds.</p>
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</td>
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<td class="code leading">
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<div class="highlight"><pre> <span class="nx">millis</span> <span class="o">:=</span> <span class="nx">nanos</span> <span class="o">/</span> <span class="mi">1000000</span>
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<span class="nx">fmt</span><span class="p">.</span><span class="nx">Println</span><span class="p">(</span><span class="nx">secs</span><span class="p">)</span>
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<span class="nx">fmt</span><span class="p">.</span><span class="nx">Println</span><span class="p">(</span><span class="nx">millis</span><span class="p">)</span>
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<span class="nx">fmt</span><span class="p">.</span><span class="nx">Println</span><span class="p">(</span><span class="nx">nanos</span><span class="p">)</span>
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</pre></div>
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</td>
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</tr>
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<tr>
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<td class="docs">
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<p>You can also convert integer seconds or nanoseconds
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since the epoch into the corresponding <code>time</code>.</p>
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</td>
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<td class="code">
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<div class="highlight"><pre> <span class="nx">fmt</span><span class="p">.</span><span class="nx">Println</span><span class="p">(</span><span class="nx">time</span><span class="p">.</span><span class="nx">Unix</span><span class="p">(</span><span class="nx">secs</span><span class="p">,</span> <span class="mi">0</span><span class="p">))</span>
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<span class="nx">fmt</span><span class="p">.</span><span class="nx">Println</span><span class="p">(</span><span class="nx">time</span><span class="p">.</span><span class="nx">Unix</span><span class="p">(</span><span class="mi">0</span><span class="p">,</span> <span class="nx">nanos</span><span class="p">))</span>
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<span class="p">}</span>
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</pre></div>
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</td>
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</tr>
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</table>
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<table>
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<tr>
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<td class="docs">
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</td>
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<td class="code leading">
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<div class="highlight"><pre><span class="gp">$</span> go run epoch.go
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<span class="go">2012-10-31 16:13:58.292387 +0000 UTC</span>
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<span class="go">1351700038</span>
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<span class="go">1351700038292</span>
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<span class="go">1351700038292387000</span>
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<span class="go">2012-10-31 16:13:58 +0000 UTC</span>
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<span class="go">2012-10-31 16:13:58.292387 +0000 UTC</span>
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</pre></div>
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</td>
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</tr>
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<tr>
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<td class="docs">
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<p>Next we’ll look at another time-related task: time
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parsing and formatting.</p>
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</td>
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<td class="code empty">
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</td>
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</tr>
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</table>
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<p class="next">
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Next example: <a href="time-formatting-parsing">Time Formatting / Parsing</a>.
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</p>
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<p class="footer">
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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/epoch">source</a> | <a href="https://github.com/mmcgrana/gobyexample#license">license</a>
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</p>
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