| <!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="Source of the Rust file `/root/.cargo/registry/src/github.com-1ecc6299db9ec823/itertools-0.8.2/src/minmax.rs`."><meta name="keywords" content="rust, rustlang, rust-lang"><title>minmax.rs - source</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="../../source-script.js"></script><script defer src="../../source-files.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 source"><!--[if lte IE 11]><div class="warning">This old browser is unsupported and will most likely display funky things.</div><![endif]--><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></nav><main><div class="width-limiter"><nav class="sub"><a class="sub-logo-container" href="../../itertools/index.html"><img class="rust-logo" src="../../rust-logo.svg" alt="logo"></a><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="example-wrap"><pre class="src-line-numbers"><span id="1">1</span> |
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| </pre><pre class="rust"><code> |
| <span class="doccomment">/// `MinMaxResult` is an enum returned by `minmax`. See `Itertools::minmax()` for |
| /// more detail. |
| </span><span class="attribute">#[derive(Copy, Clone, PartialEq, Debug)] |
| </span><span class="kw">pub enum </span>MinMaxResult<T> { |
| <span class="doccomment">/// Empty iterator |
| </span>NoElements, |
| |
| <span class="doccomment">/// Iterator with one element, so the minimum and maximum are the same |
| </span>OneElement(T), |
| |
| <span class="doccomment">/// More than one element in the iterator, the first element is not larger |
| /// than the second |
| </span>MinMax(T, T) |
| } |
| |
| <span class="kw">impl</span><T: Clone> MinMaxResult<T> { |
| <span class="doccomment">/// `into_option` creates an `Option` of type `(T, T)`. The returned `Option` |
| /// has variant `None` if and only if the `MinMaxResult` has variant |
| /// `NoElements`. Otherwise `Some((x, y))` is returned where `x <= y`. |
| /// If the `MinMaxResult` has variant `OneElement(x)`, performing this |
| /// operation will make one clone of `x`. |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// use itertools::MinMaxResult::{self, NoElements, OneElement, MinMax}; |
| /// |
| /// let r: MinMaxResult<i32> = NoElements; |
| /// assert_eq!(r.into_option(), None); |
| /// |
| /// let r = OneElement(1); |
| /// assert_eq!(r.into_option(), Some((1, 1))); |
| /// |
| /// let r = MinMax(1, 2); |
| /// assert_eq!(r.into_option(), Some((1, 2))); |
| /// ``` |
| </span><span class="kw">pub fn </span>into_option(<span class="self">self</span>) -> <span class="prelude-ty">Option</span><(T,T)> { |
| <span class="kw">match </span><span class="self">self </span>{ |
| MinMaxResult::NoElements => <span class="prelude-val">None</span>, |
| MinMaxResult::OneElement(x) => <span class="prelude-val">Some</span>((x.clone(), x)), |
| MinMaxResult::MinMax(x, y) => <span class="prelude-val">Some</span>((x, y)) |
| } |
| } |
| } |
| |
| <span class="doccomment">/// Implementation guts for `minmax` and `minmax_by_key`. |
| </span><span class="kw">pub fn </span>minmax_impl<I, K, F, L>(<span class="kw-2">mut </span>it: I, <span class="kw-2">mut </span>key_for: F, |
| <span class="kw-2">mut </span>lt: L) -> MinMaxResult<I::Item> |
| <span class="kw">where </span>I: Iterator, |
| F: FnMut(<span class="kw-2">&</span>I::Item) -> K, |
| L: FnMut(<span class="kw-2">&</span>I::Item, <span class="kw-2">&</span>I::Item, <span class="kw-2">&</span>K, <span class="kw-2">&</span>K) -> bool, |
| { |
| <span class="kw">let </span>(<span class="kw-2">mut </span>min, <span class="kw-2">mut </span>max, <span class="kw-2">mut </span>min_key, <span class="kw-2">mut </span>max_key) = <span class="kw">match </span>it.next() { |
| <span class="prelude-val">None </span>=> <span class="kw">return </span>MinMaxResult::NoElements, |
| <span class="prelude-val">Some</span>(x) => { |
| <span class="kw">match </span>it.next() { |
| <span class="prelude-val">None </span>=> <span class="kw">return </span>MinMaxResult::OneElement(x), |
| <span class="prelude-val">Some</span>(y) => { |
| <span class="kw">let </span>xk = key_for(<span class="kw-2">&</span>x); |
| <span class="kw">let </span>yk = key_for(<span class="kw-2">&</span>y); |
| <span class="kw">if </span>!lt(<span class="kw-2">&</span>y, <span class="kw-2">&</span>x, <span class="kw-2">&</span>yk, <span class="kw-2">&</span>xk) {(x, y, xk, yk)} <span class="kw">else </span>{(y, x, yk, xk)} |
| } |
| } |
| } |
| }; |
| |
| <span class="kw">loop </span>{ |
| <span class="comment">// `first` and `second` are the two next elements we want to look |
| // at. We first compare `first` and `second` (#1). The smaller one |
| // is then compared to current minimum (#2). The larger one is |
| // compared to current maximum (#3). This way we do 3 comparisons |
| // for 2 elements. |
| </span><span class="kw">let </span>first = <span class="kw">match </span>it.next() { |
| <span class="prelude-val">None </span>=> <span class="kw">break</span>, |
| <span class="prelude-val">Some</span>(x) => x |
| }; |
| <span class="kw">let </span>second = <span class="kw">match </span>it.next() { |
| <span class="prelude-val">None </span>=> { |
| <span class="kw">let </span>first_key = key_for(<span class="kw-2">&</span>first); |
| <span class="kw">if </span>lt(<span class="kw-2">&</span>first, <span class="kw-2">&</span>min, <span class="kw-2">&</span>first_key, <span class="kw-2">&</span>min_key) { |
| min = first; |
| } <span class="kw">else if </span>!lt(<span class="kw-2">&</span>first, <span class="kw-2">&</span>max, <span class="kw-2">&</span>first_key, <span class="kw-2">&</span>max_key) { |
| max = first; |
| } |
| <span class="kw">break</span>; |
| } |
| <span class="prelude-val">Some</span>(x) => x |
| }; |
| <span class="kw">let </span>first_key = key_for(<span class="kw-2">&</span>first); |
| <span class="kw">let </span>second_key = key_for(<span class="kw-2">&</span>second); |
| <span class="kw">if </span>!lt(<span class="kw-2">&</span>second, <span class="kw-2">&</span>first, <span class="kw-2">&</span>second_key, <span class="kw-2">&</span>first_key) { |
| <span class="kw">if </span>lt(<span class="kw-2">&</span>first, <span class="kw-2">&</span>min, <span class="kw-2">&</span>first_key, <span class="kw-2">&</span>min_key) { |
| min = first; |
| min_key = first_key; |
| } |
| <span class="kw">if </span>!lt(<span class="kw-2">&</span>second, <span class="kw-2">&</span>max, <span class="kw-2">&</span>second_key, <span class="kw-2">&</span>max_key) { |
| max = second; |
| max_key = second_key; |
| } |
| } <span class="kw">else </span>{ |
| <span class="kw">if </span>lt(<span class="kw-2">&</span>second, <span class="kw-2">&</span>min, <span class="kw-2">&</span>second_key, <span class="kw-2">&</span>min_key) { |
| min = second; |
| min_key = second_key; |
| } |
| <span class="kw">if </span>!lt(<span class="kw-2">&</span>first, <span class="kw-2">&</span>max, <span class="kw-2">&</span>first_key, <span class="kw-2">&</span>max_key) { |
| max = first; |
| max_key = first_key; |
| } |
| } |
| } |
| |
| MinMaxResult::MinMax(min, max) |
| } |
| </code></pre></div> |
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