| <!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="“Lift” a function of the values of an iterator so that it can process an iterator of `Result` values instead."><meta name="keywords" content="rust, rustlang, rust-lang, process_results"><title>process_results in itertools - 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="../itertools/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="../itertools/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 itertools</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">itertools</a>::<wbr><a class="fn" href="#">process_results</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/itertools/process_results_impl.rs.html#87-97">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 process_results<I, F, T, E, R>(iterable: I, processor: F) -> Result<R, E><span class="where fmt-newline">where<br> I: IntoIterator<Item = Result<T, E>>,<br> F: FnOnce(<a class="struct" href="structs/struct.ProcessResults.html" title="struct itertools::structs::ProcessResults">ProcessResults</a><'_, I::IntoIter, E>) -> R,</span></code></pre></div><details class="rustdoc-toggle top-doc" open><summary class="hideme"><span>Expand description</span></summary><div class="docblock"><p>“Lift” a function of the values of an iterator so that it can process |
| an iterator of <code>Result</code> values instead.</p> |
| <p><code>iterable</code> is an iterator or iterable with <code>Result<T, E></code> elements, where |
| <code>T</code> is the value type and <code>E</code> the error type.</p> |
| <p><code>processor</code> is a closure that receives an adapted version of the iterable |
| as the only argument — the adapted iterator produces elements of type <code>T</code>, |
| as long as the original iterator produces <code>Ok</code> values.</p> |
| <p>If the original iterable produces an error at any point, the adapted |
| iterator ends and the <code>process_results</code> function will return the |
| error iself.</p> |
| <p>Otherwise, the return value from the closure is returned wrapped |
| inside <code>Ok</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>itertools::process_results; |
| |
| <span class="kw">type </span>R = <span class="prelude-ty">Result</span><i32, <span class="kw-2">&</span><span class="lifetime">'static </span>str>; |
| |
| <span class="kw">let </span>first_values: Vec<R> = <span class="macro">vec!</span>[<span class="prelude-val">Ok</span>(<span class="number">1</span>), <span class="prelude-val">Ok</span>(<span class="number">0</span>), <span class="prelude-val">Ok</span>(<span class="number">3</span>)]; |
| <span class="kw">let </span>second_values: Vec<R> = <span class="macro">vec!</span>[<span class="prelude-val">Ok</span>(<span class="number">2</span>), <span class="prelude-val">Ok</span>(<span class="number">1</span>), <span class="prelude-val">Err</span>(<span class="string">"overflow"</span>)]; |
| |
| <span class="comment">// “Lift” the iterator .max() method to work on the values in Results using process_results |
| |
| </span><span class="kw">let </span>first_max = process_results(first_values, |iter| iter.max().unwrap_or(<span class="number">0</span>)); |
| <span class="kw">let </span>second_max = process_results(second_values, |iter| iter.max().unwrap_or(<span class="number">0</span>)); |
| |
| <span class="macro">assert_eq!</span>(first_max, <span class="prelude-val">Ok</span>(<span class="number">3</span>)); |
| <span class="macro">assert!</span>(second_max.is_err());</code></pre></div> |
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