<p>
Assigning and fetching map values looks syntactically just like
doing the same for arrays except that the index doesn't need to
-be an integer. An attempt to fetch a map value with a key that
-is not present in the map will cause the program to crash, but
-there is a way to do so safely using a multiple assignment.
+be an integer.
+</p>
+<pre>
+offset := timeZone["EST"]
+</pre>
+<p>
+An attempt to fetch a map value with a key that
+is not present in the map will return the zero value for the type
+of the entries
+in the map. For instance, if the map contains integers, looking
+up a non-existent key will return <code>0</code>.
+</p>
+<p>
+Sometimes you need to distinguish a missing entry from
+a zero value. Is there an entry for <code>"UTC"</code>
+or is that zero value because it's not in the map at all?
+You can discriminate with a form of multiple assignment.
</p>
<pre>
var seconds int
will be set appropriately and <code>ok</code> will be true; if not,
<code>seconds</code> will be set to zero and <code>ok</code> will
be false.
-Here's a function that puts it together:
+Here's a function that puts it together with a nice error report:
</p>
<pre>
func offset(tz string) int {
To test for presence in the map without worrying about the actual value,
you can use the <em>blank identifier</em>, a simple underscore (<code>_</code>).
The blank identifier can be assigned or declared with any value of any type, with the
-value discarded harmlessly. For testing presence in a map, use the blank
+value discarded harmlessly. For testing just presence in a map, use the blank
identifier in place of the usual variable for the value.
</p>
<pre>
<pre>
timeZone["PDT"] = 0, false // Now on Standard Time
</pre>
+
<h3 id="printing">Printing</h3>
<p>