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<div class="example" id="structs">
<h2><a href="./">Go by Example</a>: Structs</h2>
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<p>Go&rsquo;s <em>structs</em> are typed collections of fields.
They&rsquo;re useful for grouping data together to form
records.</p>
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<div class="highlight"><pre><span class="kn">package</span> <span class="nx">main</span>
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<div class="highlight"><pre><span class="kn">import</span> <span class="s">&quot;fmt&quot;</span>
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<p>This <code>person</code> struct type has <code>name</code> and <code>age</code> fields.</p>
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<div class="highlight"><pre><span class="kd">type</span> <span class="nx">person</span> <span class="kd">struct</span> <span class="p">{</span>
<span class="nx">name</span> <span class="kt">string</span>
<span class="nx">age</span> <span class="kt">int</span>
<span class="p">}</span>
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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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<p>This syntax creates a new struct.</p>
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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">person</span><span class="p">{</span><span class="s">&quot;Bob&quot;</span><span class="p">,</span> <span class="mi">20</span><span class="p">})</span>
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<p>You can name the fields when initializing a struct.</p>
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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">person</span><span class="p">{</span><span class="nx">name</span><span class="p">:</span> <span class="s">&quot;Alice&quot;</span><span class="p">,</span> <span class="nx">age</span><span class="p">:</span> <span class="mi">30</span><span class="p">})</span>
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<p>Omitted fields will be zero-valued.</p>
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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">person</span><span class="p">{</span><span class="nx">name</span><span class="p">:</span> <span class="s">&quot;Fred&quot;</span><span class="p">})</span>
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<p>An <code>&amp;</code> prefix yields a pointer to the struct.</p>
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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="o">&amp;</span><span class="nx">person</span><span class="p">{</span><span class="nx">name</span><span class="p">:</span> <span class="s">&quot;Ann&quot;</span><span class="p">,</span> <span class="nx">age</span><span class="p">:</span> <span class="mi">40</span><span class="p">})</span>
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<p>Access struct fields with a dot.</p>
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<div class="highlight"><pre> <span class="nx">s</span> <span class="o">:=</span> <span class="nx">person</span><span class="p">{</span><span class="nx">name</span><span class="p">:</span> <span class="s">&quot;Sean&quot;</span><span class="p">,</span> <span class="nx">age</span><span class="p">:</span> <span class="mi">50</span><span class="p">}</span>
<span class="nx">fmt</span><span class="p">.</span><span class="nx">Println</span><span class="p">(</span><span class="nx">s</span><span class="p">.</span><span class="nx">name</span><span class="p">)</span>
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<p>You can also use dots with struct pointers - the
pointers are automatically dereferenced.</p>
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<div class="highlight"><pre> <span class="nx">sp</span> <span class="o">:=</span> <span class="o">&amp;</span><span class="nx">s</span>
<span class="nx">fmt</span><span class="p">.</span><span class="nx">Println</span><span class="p">(</span><span class="nx">sp</span><span class="p">.</span><span class="nx">age</span><span class="p">)</span>
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<p>Structs are mutable.</p>
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<div class="highlight"><pre> <span class="nx">sp</span><span class="p">.</span><span class="nx">age</span> <span class="p">=</span> <span class="mi">51</span>
<span class="nx">fmt</span><span class="p">.</span><span class="nx">Println</span><span class="p">(</span><span class="nx">sp</span><span class="p">.</span><span class="nx">age</span><span class="p">)</span>
<span class="p">}</span>
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<div class="highlight"><pre><span class="gp">$</span> go run structs.go
<span class="go">{Bob 20}</span>
<span class="go">{Alice 30}</span>
<span class="go">{Fred 0}</span>
<span class="go">&amp;{Ann 40}</span>
<span class="go">Sean</span>
<span class="go">50</span>
<span class="go">51</span>
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<p class="next">
Next example: <a href="methods">Methods</a>.
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