161 lines
7.5 KiB
HTML
161 lines
7.5 KiB
HTML
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<!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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<meta name="viewport" content="width=device-width, initial-scale=1.0">
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<meta name="generator" content="rustdoc">
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<meta name="description" content="API documentation for the Rust `from_value` fn in crate `serde_json`.">
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<meta name="keywords" content="rust, rustlang, rust-lang, from_value">
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<title>serde_json::from_value - Rust</title>
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<link rel="stylesheet" type="text/css" href="../normalize.css">
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<link rel="stylesheet" type="text/css" href="../rustdoc.css" id="mainThemeStyle">
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</head>
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<body class="rustdoc fn">
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<div class="warning">
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This old browser is unsupported and will most likely display funky
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things.
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<![endif]-->
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<nav class="sidebar">
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<div class="sidebar-menu">☰</div>
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<p class='location'><a href='index.html'>serde_json</a></p><script>window.sidebarCurrent = {name: 'from_value', ty: 'fn', relpath: ''};</script><script defer src="sidebar-items.js"></script>
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<nav class="sub">
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<form class="search-form js-only">
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<div class="search-container">
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<input class="search-input" name="search"
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autocomplete="off"
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placeholder="Click or press ‘S’ to search, ‘?’ for more options…"
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type="search">
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</div>
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</form>
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</nav>
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<section id='main' class="content">
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<h1 class='fqn'><span class='in-band'>Function <a href='index.html'>serde_json</a>::<wbr><a class="fn" href=''>from_value</a></span><span class='out-of-band'><span id='render-detail'>
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<a id="toggle-all-docs" href="javascript:void(0)" title="collapse all docs">
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[<span class='inner'>−</span>]
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</a>
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</span><a class='srclink' href='../src/serde_json/value/mod.rs.html#1121-1126' title='goto source code'>[src]</a></span></h1>
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<pre class='rust fn'>pub fn from_value<T>(value: <a class="enum" href="../serde_json/value/enum.Value.html" title="enum serde_json::value::Value">Value</a>) -> <a class="enum" href="https://doc.rust-lang.org/nightly/core/result/enum.Result.html" title="enum core::result::Result">Result</a><T, <a class="struct" href="../serde_json/error/struct.Error.html" title="struct serde_json::error::Error">Error</a>> <span class="where fmt-newline">where<br> T: <a class="trait" href="../serde/de/trait.DeserializeOwned.html" title="trait serde::de::DeserializeOwned">DeserializeOwned</a>, </span></pre><div class='docblock'><p>Interpret a <code>serde_json::Value</code> as an instance of type <code>T</code>.</p>
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<p>This conversion can fail if the structure of the Value does not match the
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structure expected by <code>T</code>, for example if <code>T</code> is a struct type but the Value
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contains something other than a JSON map. It can also fail if the structure
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is correct but <code>T</code>'s implementation of <code>Deserialize</code> decides that something
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is wrong with the data, for example required struct fields are missing from
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the JSON map or some number is too big to fit in the expected primitive
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type.</p>
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<pre class="rust rust-example-rendered">
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<span class="attribute">#[<span class="ident">macro_use</span>]</span>
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<span class="kw">extern</span> <span class="kw">crate</span> <span class="ident">serde_json</span>;
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<span class="attribute">#[<span class="ident">macro_use</span>]</span>
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<span class="kw">extern</span> <span class="kw">crate</span> <span class="ident">serde_derive</span>;
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<span class="kw">extern</span> <span class="kw">crate</span> <span class="ident">serde</span>;
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<span class="attribute">#[<span class="ident">derive</span>(<span class="ident">Deserialize</span>, <span class="ident">Debug</span>)]</span>
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<span class="kw">struct</span> <span class="ident">User</span> {
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<span class="ident">fingerprint</span>: <span class="ident">String</span>,
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<span class="ident">location</span>: <span class="ident">String</span>,
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}
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<span class="kw">fn</span> <span class="ident">main</span>() {
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<span class="comment">// The type of `j` is `serde_json::Value`</span>
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<span class="kw">let</span> <span class="ident">j</span> <span class="op">=</span> <span class="macro">json</span><span class="macro">!</span>({
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<span class="string">"fingerprint"</span>: <span class="string">"0xF9BA143B95FF6D82"</span>,
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<span class="string">"location"</span>: <span class="string">"Menlo Park, CA"</span>
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});
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<span class="kw">let</span> <span class="ident">u</span>: <span class="ident">User</span> <span class="op">=</span> <span class="ident">serde_json</span>::<span class="ident">from_value</span>(<span class="ident">j</span>).<span class="ident">unwrap</span>();
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<span class="macro">println</span><span class="macro">!</span>(<span class="string">"{:#?}"</span>, <span class="ident">u</span>);
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}</pre>
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</div></section>
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<section id='search' class="content hidden"></section>
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<section class="footer"></section>
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<aside id="help" class="hidden">
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<div>
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<h1 class="hidden">Help</h1>
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<div class="shortcuts">
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<h2>Keyboard Shortcuts</h2>
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<dl>
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<dt><kbd>?</kbd></dt>
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<dd>Show this help dialog</dd>
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<dd>Focus the search field</dd>
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<dd>Collapse all sections</dd>
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</dl>
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</div>
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<div class="infos">
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<h2>Search Tricks</h2>
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<p>
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Prefix searches with a type followed by a colon (e.g.
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<code>fn:</code>) to restrict the search to a given type.
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</p>
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<p>
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Accepted types are: <code>fn</code>, <code>mod</code>,
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<code>struct</code>, <code>enum</code>,
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<code>trait</code>, <code>type</code>, <code>macro</code>,
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and <code>const</code>.
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</p>
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<p>
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Search functions by type signature (e.g.
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<code>vec -> usize</code> or <code>* -> vec</code>)
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</p>
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</div>
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</div>
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</aside>
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<script>
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window.rootPath = "../";
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window.currentCrate = "serde_json";
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</script>
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<script src="../main.js"></script>
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<script defer src="../search-index.js"></script>
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</body>
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</html>
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