31 lines
1.6 KiB
HTML
31 lines
1.6 KiB
HTML
<!DOCTYPE html>
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<html lang="en">
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<head>
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<meta charset="UTF-8">
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<title>Common Collections</title>
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</head>
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<body>
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<h1 id="common-collections"><a class="header" href="#common-collections">Common Collections</a></h1>
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<p>Rust’s standard library includes a number of very useful data structures called
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<em>collections</em>. Most other data types represent one specific value, but
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collections can contain multiple values. Unlike the built-in array and tuple
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types, the data that these collections point to is stored on the heap, which
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means the amount of data does not need to be known at compile time and can grow
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or shrink as the program runs. Each kind of collection has different
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capabilities and costs, and choosing an appropriate one for your current
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situation is a skill you’ll develop over time. In this chapter, we’ll discuss
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three collections that are used very often in Rust programs:</p>
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<ul>
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<li>A <em>vector</em> allows you to store a variable number of values next to each other.</li>
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<li>A <em>string</em> is a collection of characters. We’ve mentioned the <code>String</code> type
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previously, but in this chapter, we’ll talk about it in depth.</li>
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<li>A <em>hash map</em> allows you to associate a value with a specific key. It’s a
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particular implementation of the more general data structure called a <em>map</em>.</li>
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</ul>
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<p>To learn about the other kinds of collections provided by the standard library,
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see <a href="../std/collections/index.html">the documentation</a>.</p>
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<p>We’ll discuss how to create and update vectors, strings, and hash maps, as well
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as what makes each special.</p>
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</body>
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</html>
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