Mirror/wren
1
0
Fork 1
mirror of https://github.com/wren-lang/wren.git synced 2026-01-11 22:28:45 +01:00
Code Issues Packages Projects Releases Wiki Activity

Regenerate docs.

Browse Source
This commit is contained in:
Bob Nystrom
2015-09-22 08:02:21 -07:00
parent 734b275c4a
commit 61c1c991b1
33 changed files with 624 additions and 602 deletions
Download Patch File Download Diff File Expand all files Collapse all files

52
maps.html
View File

@ -65,10 +65,10 @@ other languages: hash table, dictionary, association, table, etc.</p>
<p>You can create a map by placing a series of comma-separated entries inside
curly braces. Each entry is a key and a value separated by a colon:</p>
<div class="codehilite"><pre><span class="p">{</span>
<span class="s2">&quot;George&quot;</span><span class="o">:</span> <span class="s2">&quot;Harrison&quot;</span><span class="p">,</span>
<span class="s2">&quot;John&quot;</span><span class="o">:</span> <span class="s2">&quot;Lennon&quot;</span><span class="p">,</span>
<span class="s2">&quot;Paul&quot;</span><span class="o">:</span> <span class="s2">&quot;McCartney&quot;</span><span class="p">,</span>
<span class="s2">&quot;Ringo&quot;</span><span class="o">:</span> <span class="s2">&quot;Starr&quot;</span>
<span class="s">&quot;George&quot;</span><span class="o">:</span> <span class="s">&quot;Harrison&quot;</span><span class="p">,</span>
<span class="s">&quot;John&quot;</span><span class="o">:</span> <span class="s">&quot;Lennon&quot;</span><span class="p">,</span>
<span class="s">&quot;Paul&quot;</span><span class="o">:</span> <span class="s">&quot;McCartney&quot;</span><span class="p">,</span>
<span class="s">&quot;Ringo&quot;</span><span class="o">:</span> <span class="s">&quot;Starr&quot;</span>
<span class="p">}</span>
</pre></div>
@ -92,10 +92,10 @@ time, even in very large maps. Since Wren only knows how to hash certain
built-in types, only those can be used as keys.</p>
<h2>Adding entries <a href="#adding-entries" name="adding-entries" class="header-anchor">#</a></h2>
<p>You add new key-value pairs to the map by using the <a href="expressions.html#subscript-operators">subscript operator</a>:</p>
<div class="codehilite"><pre><span class="kd">var</span> <span class="n">capitals</span> <span class="o">=</span> <span class="p">{}</span>
<span class="n">capitals</span><span class="p">[</span><span class="s2">&quot;Georgia&quot;</span><span class="p">]</span> <span class="o">=</span> <span class="s2">&quot;Atlanta&quot;</span>
<span class="n">capitals</span><span class="p">[</span><span class="s2">&quot;Idaho&quot;</span><span class="p">]</span> <span class="o">=</span> <span class="s2">&quot;Boise&quot;</span>
<span class="n">capitals</span><span class="p">[</span><span class="s2">&quot;Maine&quot;</span><span class="p">]</span> <span class="o">=</span> <span class="s2">&quot;Augusta&quot;</span>
<div class="codehilite"><pre><span class="k">var</span> <span class="n">capitals</span> <span class="o">=</span> <span class="p">{}</span>
<span class="n">capitals</span><span class="p">[</span><span class="s">&quot;Georgia&quot;</span><span class="p">]</span> <span class="o">=</span> <span class="s">&quot;Atlanta&quot;</span>
<span class="n">capitals</span><span class="p">[</span><span class="s">&quot;Idaho&quot;</span><span class="p">]</span> <span class="o">=</span> <span class="s">&quot;Boise&quot;</span>
<span class="n">capitals</span><span class="p">[</span><span class="s">&quot;Maine&quot;</span><span class="p">]</span> <span class="o">=</span> <span class="s">&quot;Augusta&quot;</span>
</pre></div>
@ -104,7 +104,7 @@ value. If the key is already there, this just replaces its value.</p>
<h2>Looking up values <a href="#looking-up-values" name="looking-up-values" class="header-anchor">#</a></h2>
<p>To find the value associated with some key, again you use your friend the
subscript operator:</p>
<div class="codehilite"><pre><span class="n">IO</span><span class="p">.</span><span class="n">print</span><span class="p">(</span><span class="n">capitals</span><span class="p">[</span><span class="s2">&quot;Idaho&quot;</span><span class="p">])</span> <span class="c1">// &quot;Boise&quot;.</span>
<div class="codehilite"><pre><span class="vg">System</span><span class="o">.</span><span class="n">print</span><span class="p">(</span><span class="n">capitals</span><span class="p">[</span><span class="s">&quot;Idaho&quot;</span><span class="p">])</span> <span class="c1">// &quot;Boise&quot;.</span>
</pre></div>
@ -112,38 +112,38 @@ subscript operator:</p>
course, <code>null</code> itself can also be used as a value, so seeing <code>null</code> here
doesn't necessarily mean the key wasn't found.</p>
<p>To tell definitively if a key exists, you can call <code>containsKey()</code>:</p>
<div class="codehilite"><pre><span class="kd">var</span> <span class="n">belief</span> <span class="o">=</span> <span class="p">{</span><span class="s2">&quot;nihilism&quot;</span><span class="o">:</span> <span class="kc">null</span><span class="p">}</span>
<div class="codehilite"><pre><span class="k">var</span> <span class="n">belief</span> <span class="o">=</span> <span class="p">{</span><span class="s">&quot;nihilism&quot;</span><span class="o">:</span> <span class="kc">null</span><span class="p">}</span>
<span class="n">IO</span><span class="p">.</span><span class="n">print</span><span class="p">(</span><span class="n">belief</span><span class="p">[</span><span class="s2">&quot;nihilism&quot;</span><span class="p">])</span> <span class="c1">// &quot;null&quot; though key exists.</span>
<span class="n">IO</span><span class="p">.</span><span class="n">print</span><span class="p">(</span><span class="n">belief</span><span class="p">[</span><span class="s2">&quot;solipsism&quot;</span><span class="p">])</span> <span class="c1">// Also &quot;null&quot;.</span>
<span class="n">IO</span><span class="p">.</span><span class="n">print</span><span class="p">(</span><span class="n">belief</span><span class="p">.</span><span class="n">containsKey</span><span class="p">(</span><span class="s2">&quot;nihilism&quot;</span><span class="p">))</span> <span class="c1">// &quot;true&quot;.</span>
<span class="n">IO</span><span class="p">.</span><span class="n">print</span><span class="p">(</span><span class="n">belief</span><span class="p">.</span><span class="n">containsKey</span><span class="p">(</span><span class="s2">&quot;solipsism&quot;</span><span class="p">))</span> <span class="c1">// &quot;false&quot;.</span>
<span class="vg">System</span><span class="o">.</span><span class="n">print</span><span class="p">(</span><span class="n">belief</span><span class="p">[</span><span class="s">&quot;nihilism&quot;</span><span class="p">])</span> <span class="c1">// &quot;null&quot; though key exists.</span>
<span class="vg">System</span><span class="o">.</span><span class="n">print</span><span class="p">(</span><span class="n">belief</span><span class="p">[</span><span class="s">&quot;solipsism&quot;</span><span class="p">])</span> <span class="c1">// Also &quot;null&quot;.</span>
<span class="vg">System</span><span class="o">.</span><span class="n">print</span><span class="p">(</span><span class="n">belief</span><span class="o">.</span><span class="n">containsKey</span><span class="p">(</span><span class="s">&quot;nihilism&quot;</span><span class="p">))</span> <span class="c1">// &quot;true&quot;.</span>
<span class="vg">System</span><span class="o">.</span><span class="n">print</span><span class="p">(</span><span class="n">belief</span><span class="o">.</span><span class="n">containsKey</span><span class="p">(</span><span class="s">&quot;solipsism&quot;</span><span class="p">))</span> <span class="c1">// &quot;false&quot;.</span>
</pre></div>
<p>You can see how many entries a map contains using <code>count</code>:</p>
<div class="codehilite"><pre><span class="n">IO</span><span class="p">.</span><span class="n">print</span><span class="p">(</span><span class="n">capitals</span><span class="p">.</span><span class="n">count</span><span class="p">)</span> <span class="c1">// &quot;3&quot;.</span>
<div class="codehilite"><pre><span class="vg">System</span><span class="o">.</span><span class="n">print</span><span class="p">(</span><span class="n">capitals</span><span class="o">.</span><span class="n">count</span><span class="p">)</span> <span class="c1">// &quot;3&quot;.</span>
</pre></div>
<h2>Removing entries <a href="#removing-entries" name="removing-entries" class="header-anchor">#</a></h2>
<p>To remove an entry from a map, call <code>remove()</code> and pass in the key for the
entry you want to delete:</p>
<div class="codehilite"><pre><span class="n">capitals</span><span class="p">.</span><span class="n">remove</span><span class="p">(</span><span class="s2">&quot;Maine&quot;</span><span class="p">)</span>
<span class="n">IO</span><span class="p">.</span><span class="n">print</span><span class="p">(</span><span class="n">capitals</span><span class="p">.</span><span class="n">containsKey</span><span class="p">(</span><span class="s2">&quot;Maine&quot;</span><span class="p">))</span> <span class="c1">// &quot;false&quot;.</span>
<div class="codehilite"><pre><span class="n">capitals</span><span class="o">.</span><span class="n">remove</span><span class="p">(</span><span class="s">&quot;Maine&quot;</span><span class="p">)</span>
<span class="vg">System</span><span class="o">.</span><span class="n">print</span><span class="p">(</span><span class="n">capitals</span><span class="o">.</span><span class="n">containsKey</span><span class="p">(</span><span class="s">&quot;Maine&quot;</span><span class="p">))</span> <span class="c1">// &quot;false&quot;.</span>
</pre></div>
<p>If the key was found, this returns the value that was associated with it:</p>
<div class="codehilite"><pre><span class="n">IO</span><span class="p">.</span><span class="n">print</span><span class="p">(</span><span class="n">capitals</span><span class="p">.</span><span class="n">remove</span><span class="p">(</span><span class="s2">&quot;Georgia&quot;</span><span class="p">))</span> <span class="c1">// &quot;Atlanta&quot;.</span>
<div class="codehilite"><pre><span class="vg">System</span><span class="o">.</span><span class="n">print</span><span class="p">(</span><span class="n">capitals</span><span class="o">.</span><span class="n">remove</span><span class="p">(</span><span class="s">&quot;Georgia&quot;</span><span class="p">))</span> <span class="c1">// &quot;Atlanta&quot;.</span>
</pre></div>
<p>If the key wasn't in the map to begin with, <code>remove()</code> just returns <code>null</code>.</p>
<p>If you want to remove <em>everything</em> from the map, just like with <a href="lists.html">lists</a>, you
can just call <code>clear()</code>:</p>
<div class="codehilite"><pre><span class="n">capitals</span><span class="p">.</span><span class="n">clear</span><span class="p">()</span>
<span class="n">IO</span><span class="p">.</span><span class="n">print</span><span class="p">(</span><span class="n">capitals</span><span class="p">.</span><span class="n">count</span><span class="p">)</span> <span class="c1">// &quot;0&quot;.</span>
<div class="codehilite"><pre><span class="n">capitals</span><span class="o">.</span><span class="n">clear</span><span class="p">()</span>
<span class="vg">System</span><span class="o">.</span><span class="n">print</span><span class="p">(</span><span class="n">capitals</span><span class="o">.</span><span class="n">count</span><span class="p">)</span> <span class="c1">// &quot;0&quot;.</span>
</pre></div>
@ -155,14 +155,14 @@ For that, map exposes two methods: <code>keys</code> and <code>values</code>.</p
map, and the second returns one that iterates over the values.</p>
<p>If you want to see all of the key-value pairs in a map, the easiest way is to
iterate over the keys and use each to look up its value:</p>
<div class="codehilite"><pre><span class="kd">var</span> <span class="n">stateBirds</span> <span class="o">=</span> <span class="p">{</span>
<span class="s2">&quot;Arizona&quot;</span><span class="o">:</span> <span class="s2">&quot;Cactus wren&quot;</span><span class="p">,</span>
<span class="s2">&quot;Hawaii&quot;</span><span class="o">:</span> <span class="s2">&quot;Nēnē&quot;</span><span class="p">,</span>
<span class="s2">&quot;Ohio&quot;</span><span class="o">:</span> <span class="s2">&quot;Northern Cardinal&quot;</span>
<div class="codehilite"><pre><span class="k">var</span> <span class="n">birds</span> <span class="o">=</span> <span class="p">{</span>
<span class="s">&quot;Arizona&quot;</span><span class="o">:</span> <span class="s">&quot;Cactus wren&quot;</span><span class="p">,</span>
<span class="s">&quot;Hawaii&quot;</span><span class="o">:</span> <span class="s">&quot;Nēnē&quot;</span><span class="p">,</span>
<span class="s">&quot;Ohio&quot;</span><span class="o">:</span> <span class="s">&quot;Northern Cardinal&quot;</span>
<span class="p">}</span>
<span class="k">for</span> <span class="p">(</span><span class="n">state</span> <span class="k">in</span> <span class="n">stateBirds</span><span class="p">.</span><span class="n">keys</span><span class="p">)</span> <span class="p">{</span>
<span class="n">IO</span><span class="p">.</span><span class="n">print</span><span class="p">(</span><span class="s2">&quot;The state bird of &quot;</span><span class="p">,</span> <span class="n">state</span><span class="p">,</span> <span class="s2">&quot; is &quot;</span><span class="p">,</span> <span class="n">stateBirds</span><span class="p">[</span><span class="n">state</span><span class="p">])</span>
<span class="k">for</span> <span class="p">(</span><span class="n">state</span> <span class="k">in</span> <span class="n">birds</span><span class="o">.</span><span class="n">keys</span><span class="p">)</span> <span class="p">{</span>
<span class="vg">System</span><span class="o">.</span><span class="n">print</span><span class="p">(</span><span class="s">&quot;The state bird of &quot;</span> <span class="o">+</span> <span class="n">state</span> <span class="o">+</span> <span class="s">&quot; is &quot;</span> <span class="o">+</span> <span class="n">birds</span><span class="p">[</span><span class="n">state</span><span class="p">])</span>
<span class="p">}</span>
</pre></div>