From 0812429584978a95f3d4475011695608a2d95d88 Mon Sep 17 00:00:00 2001
From: Eli Bendersky <eliben@gmail.com>
Date: Mon, 20 Mar 2023 05:59:53 -0700
Subject: [PATCH] Clarify zero value for map values when keys don't exist

---
 examples/maps/maps.go   |  8 +++++++-
 examples/maps/maps.hash |  4 ++--
 examples/maps/maps.sh   |  3 ++-
 public/maps             | 25 +++++++++++++++++++++----
 4 files changed, 32 insertions(+), 8 deletions(-)

diff --git a/examples/maps/maps.go b/examples/maps/maps.go
index 8a40d35..441e2a3 100644
--- a/examples/maps/maps.go
+++ b/examples/maps/maps.go
@@ -22,7 +22,13 @@ func main() {
 
 	// Get a value for a key with `name[key]`.
 	v1 := m["k1"]
-	fmt.Println("v1: ", v1)
+	fmt.Println("v1:", v1)
+
+	// If the key doesn't exist, the
+	// [zero value](https://go.dev/ref/spec#The_zero_value) of the
+	// value type is returned.
+	v3 := m["k3"]
+	fmt.Println("v3:", v3)
 
 	// The builtin `len` returns the number of key/value
 	// pairs when called on a map.
diff --git a/examples/maps/maps.hash b/examples/maps/maps.hash
index 2c0cd81..9dcd6b8 100644
--- a/examples/maps/maps.hash
+++ b/examples/maps/maps.hash
@@ -1,2 +1,2 @@
-22d147fe9402f9ff210f12b9810811c07f4d64ca
-ulCzODwCde_0
+0d764945481b4960c573e67f7d303166b750413e
+xl_teZEVqbo
diff --git a/examples/maps/maps.sh b/examples/maps/maps.sh
index da7a841..56f3be1 100644
--- a/examples/maps/maps.sh
+++ b/examples/maps/maps.sh
@@ -2,7 +2,8 @@
 # printed with `fmt.Println`.
 $ go run maps.go 
 map: map[k1:7 k2:13]
-v1:  7
+v1: 7
+v3: 0
 len: 2
 map: map[k1:7]
 prs: false
diff --git a/public/maps b/public/maps
index bf99e93..8e64a84 100644
--- a/public/maps
+++ b/public/maps
@@ -42,7 +42,7 @@
             
           </td>
           <td class="code leading">
-            <a href="https://go.dev/play/p/ulCzODwCde_0"><img title="Run code" src="play.png" class="run" /></a><img title="Copy code" src="clipboard.png" class="copy" />
+            <a href="https://go.dev/play/p/xl_teZEVqbo"><img title="Run code" src="play.png" class="run" /></a><img title="Copy code" src="clipboard.png" class="copy" />
           <pre class="chroma"><span class="kn">package</span> <span class="nx">main</span>
 </pre>
           </td>
@@ -122,7 +122,23 @@ its key/value pairs.</p>
             
           <pre class="chroma">
     <span class="nx">v1</span> <span class="o">:=</span> <span class="nx">m</span><span class="p">[</span><span class="s">&#34;k1&#34;</span><span class="p">]</span>
-    <span class="nx">fmt</span><span class="p">.</span><span class="nf">Println</span><span class="p">(</span><span class="s">&#34;v1: &#34;</span><span class="p">,</span> <span class="nx">v1</span><span class="p">)</span>
+    <span class="nx">fmt</span><span class="p">.</span><span class="nf">Println</span><span class="p">(</span><span class="s">&#34;v1:&#34;</span><span class="p">,</span> <span class="nx">v1</span><span class="p">)</span>
+</pre>
+          </td>
+        </tr>
+        
+        <tr>
+          <td class="docs">
+            <p>If the key doesn&rsquo;t exist, the
+<a href="https://go.dev/ref/spec#The_zero_value">zero value</a> of the
+value type is returned.</p>
+
+          </td>
+          <td class="code leading">
+            
+          <pre class="chroma">
+    <span class="nx">v3</span> <span class="o">:=</span> <span class="nx">m</span><span class="p">[</span><span class="s">&#34;k3&#34;</span><span class="p">]</span>
+    <span class="nx">fmt</span><span class="p">.</span><span class="nf">Println</span><span class="p">(</span><span class="s">&#34;v3:&#34;</span><span class="p">,</span> <span class="nx">v3</span><span class="p">)</span>
 </pre>
           </td>
         </tr>
@@ -207,7 +223,8 @@ printed with <code>fmt.Println</code>.</p>
           <pre class="chroma">
 <span class="gp">$</span> go run maps.go 
 <span class="go">map: map[k1:7 k2:13]
-</span><span class="go">v1:  7
+</span><span class="go">v1: 7
+</span><span class="go">v3: 0
 </span><span class="go">len: 2
 </span><span class="go">map: map[k1:7]
 </span><span class="go">prs: false
@@ -230,7 +247,7 @@ printed with <code>fmt.Println</code>.</p>
     </div>
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