| <!DOCTYPE html><html lang="en"><head><meta charset="utf-8"><meta name="viewport" content="width=device-width, initial-scale=1.0"><meta name="generator" content="rustdoc"><meta name="description" content="Interpret a `serde_json::Value` as an instance of type `T`."><meta name="keywords" content="rust, rustlang, rust-lang, from_value"><title>from_value in serde_json - Rust</title><link rel="preload" as="font" type="font/woff2" crossorigin href="../SourceSerif4-Regular.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../FiraSans-Regular.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../FiraSans-Medium.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../SourceCodePro-Regular.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../SourceSerif4-Bold.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../SourceCodePro-Semibold.ttf.woff2"><link rel="stylesheet" href="../normalize.css"><link rel="stylesheet" href="../rustdoc.css" id="mainThemeStyle"><link rel="stylesheet" href="../ayu.css" disabled><link rel="stylesheet" href="../dark.css" disabled><link rel="stylesheet" href="../light.css" id="themeStyle"><script id="default-settings" ></script><script src="../storage.js"></script><script defer src="sidebar-items.js"></script><script defer src="../main.js"></script><noscript><link rel="stylesheet" href="../noscript.css"></noscript><link rel="alternate icon" type="image/png" href="../favicon-16x16.png"><link rel="alternate icon" type="image/png" href="../favicon-32x32.png"><link rel="icon" type="image/svg+xml" href="../favicon.svg"></head><body class="rustdoc fn"><!--[if lte IE 11]><div class="warning">This old browser is unsupported and will most likely display funky things.</div><![endif]--><nav class="mobile-topbar"><button class="sidebar-menu-toggle">☰</button><a class="sidebar-logo" href="../serde_json/index.html"><div class="logo-container"><img class="rust-logo" src="../rust-logo.svg" alt="logo"></div></a><h2></h2></nav><nav class="sidebar"><a class="sidebar-logo" href="../serde_json/index.html"><div class="logo-container"><img class="rust-logo" src="../rust-logo.svg" alt="logo"></div></a><div class="sidebar-elems"><h2><a href="index.html">In serde_json</a></h2></div></nav><main><div class="width-limiter"><nav class="sub"><form class="search-form"><div class="search-container"><span></span><input class="search-input" name="search" autocomplete="off" spellcheck="false" placeholder="Click or press ‘S’ to search, ‘?’ for more options…" type="search"><div id="help-button" title="help" tabindex="-1"><a href="../help.html">?</a></div><div id="settings-menu" tabindex="-1"><a href="../settings.html" title="settings"><img width="22" height="22" alt="Change settings" src="../wheel.svg"></a></div></div></form></nav><section id="main-content" class="content"><div class="main-heading"><h1 class="fqn">Function <a href="index.html">serde_json</a>::<wbr><a class="fn" href="#">from_value</a><button id="copy-path" onclick="copy_path(this)" title="Copy item path to clipboard"><img src="../clipboard.svg" width="19" height="18" alt="Copy item path"></button></h1><span class="out-of-band"><a class="srclink" href="../src/serde_json/value/mod.rs.html#982-987">source</a> · <a id="toggle-all-docs" href="javascript:void(0)" title="collapse all docs">[<span class="inner">−</span>]</a></span></div><div class="item-decl"><pre class="rust fn"><code>pub fn from_value<T>(value: <a class="enum" href="enum.Value.html" title="enum serde_json::Value">Value</a>) -> Result<T, <a class="struct" href="struct.Error.html" title="struct serde_json::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></code></pre></div><details class="rustdoc-toggle top-doc" open><summary class="hideme"><span>Expand description</span></summary><div class="docblock"><p>Interpret a <code>serde_json::Value</code> as an instance of type <code>T</code>.</p> |
| <h2 id="example"><a href="#example">Example</a></h2> |
| <div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>serde::Deserialize; |
| <span class="kw">use </span>serde_json::json; |
| |
| <span class="attribute">#[derive(Deserialize, Debug)] |
| </span><span class="kw">struct </span>User { |
| fingerprint: String, |
| location: String, |
| } |
| |
| <span class="kw">fn </span>main() { |
| <span class="comment">// The type of `j` is `serde_json::Value` |
| </span><span class="kw">let </span>j = <span class="macro">json!</span>({ |
| <span class="string">"fingerprint"</span>: <span class="string">"0xF9BA143B95FF6D82"</span>, |
| <span class="string">"location"</span>: <span class="string">"Menlo Park, CA" |
| </span>}); |
| |
| <span class="kw">let </span>u: User = serde_json::from_value(j).unwrap(); |
| <span class="macro">println!</span>(<span class="string">"{:#?}"</span>, u); |
| }</code></pre></div> |
| <h2 id="errors"><a href="#errors">Errors</a></h2> |
| <p>This conversion can fail if the structure of the Value does not match the |
| structure expected by <code>T</code>, for example if <code>T</code> is a struct type but the Value |
| contains something other than a JSON map. It can also fail if the structure |
| is correct but <code>T</code>’s implementation of <code>Deserialize</code> decides that something |
| is wrong with the data, for example required struct fields are missing from |
| the JSON map or some number is too big to fit in the expected primitive |
| type.</p> |
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