| <!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-0.10.5/src/combinations_with_replacement.rs`."><meta name="keywords" content="rust, rustlang, rust-lang"><title>combinations_with_replacement.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="kw">use </span>alloc::vec::Vec; |
| <span class="kw">use </span>std::fmt; |
| <span class="kw">use </span>std::iter::FusedIterator; |
| |
| <span class="kw">use </span><span class="kw">super</span>::lazy_buffer::LazyBuffer; |
| |
| <span class="doccomment">/// An iterator to iterate through all the `n`-length combinations in an iterator, with replacement. |
| /// |
| /// See [`.combinations_with_replacement()`](crate::Itertools::combinations_with_replacement) |
| /// for more information. |
| </span><span class="attribute">#[derive(Clone)] |
| </span><span class="kw">pub struct </span>CombinationsWithReplacement<I> |
| <span class="kw">where |
| </span>I: Iterator, |
| I::Item: Clone, |
| { |
| indices: Vec<usize>, |
| pool: LazyBuffer<I>, |
| first: bool, |
| } |
| |
| <span class="kw">impl</span><I> fmt::Debug <span class="kw">for </span>CombinationsWithReplacement<I> |
| <span class="kw">where |
| </span>I: Iterator + fmt::Debug, |
| I::Item: fmt::Debug + Clone, |
| { |
| <span class="macro">debug_fmt_fields!</span>(Combinations, indices, pool, first); |
| } |
| |
| <span class="kw">impl</span><I> CombinationsWithReplacement<I> |
| <span class="kw">where |
| </span>I: Iterator, |
| I::Item: Clone, |
| { |
| <span class="doccomment">/// Map the current mask over the pool to get an output combination |
| </span><span class="kw">fn </span>current(<span class="kw-2">&</span><span class="self">self</span>) -> Vec<I::Item> { |
| <span class="self">self</span>.indices.iter().map(|i| <span class="self">self</span>.pool[<span class="kw-2">*</span>i].clone()).collect() |
| } |
| } |
| |
| <span class="doccomment">/// Create a new `CombinationsWithReplacement` from a clonable iterator. |
| </span><span class="kw">pub fn </span>combinations_with_replacement<I>(iter: I, k: usize) -> CombinationsWithReplacement<I> |
| <span class="kw">where |
| </span>I: Iterator, |
| I::Item: Clone, |
| { |
| <span class="kw">let </span>indices: Vec<usize> = <span class="macro">alloc::vec!</span>[<span class="number">0</span>; k]; |
| <span class="kw">let </span>pool: LazyBuffer<I> = LazyBuffer::new(iter); |
| |
| CombinationsWithReplacement { |
| indices, |
| pool, |
| first: <span class="bool-val">true</span>, |
| } |
| } |
| |
| <span class="kw">impl</span><I> Iterator <span class="kw">for </span>CombinationsWithReplacement<I> |
| <span class="kw">where |
| </span>I: Iterator, |
| I::Item: Clone, |
| { |
| <span class="kw">type </span>Item = Vec<I::Item>; |
| <span class="kw">fn </span>next(<span class="kw-2">&mut </span><span class="self">self</span>) -> <span class="prelude-ty">Option</span><<span class="self">Self</span>::Item> { |
| <span class="comment">// If this is the first iteration, return early |
| </span><span class="kw">if </span><span class="self">self</span>.first { |
| <span class="comment">// In empty edge cases, stop iterating immediately |
| </span><span class="kw">return if </span>!(<span class="self">self</span>.indices.is_empty() || <span class="self">self</span>.pool.get_next()) { |
| <span class="prelude-val">None |
| </span><span class="comment">// Otherwise, yield the initial state |
| </span>} <span class="kw">else </span>{ |
| <span class="self">self</span>.first = <span class="bool-val">false</span>; |
| <span class="prelude-val">Some</span>(<span class="self">self</span>.current()) |
| }; |
| } |
| |
| <span class="comment">// Check if we need to consume more from the iterator |
| // This will run while we increment our first index digit |
| </span><span class="self">self</span>.pool.get_next(); |
| |
| <span class="comment">// Work out where we need to update our indices |
| </span><span class="kw">let </span><span class="kw-2">mut </span>increment: <span class="prelude-ty">Option</span><(usize, usize)> = <span class="prelude-val">None</span>; |
| <span class="kw">for </span>(i, indices_int) <span class="kw">in </span><span class="self">self</span>.indices.iter().enumerate().rev() { |
| <span class="kw">if </span><span class="kw-2">*</span>indices_int < <span class="self">self</span>.pool.len()-<span class="number">1 </span>{ |
| increment = <span class="prelude-val">Some</span>((i, indices_int + <span class="number">1</span>)); |
| <span class="kw">break</span>; |
| } |
| } |
| |
| <span class="kw">match </span>increment { |
| <span class="comment">// If we can update the indices further |
| </span><span class="prelude-val">Some</span>((increment_from, increment_value)) => { |
| <span class="comment">// We need to update the rightmost non-max value |
| // and all those to the right |
| </span><span class="kw">for </span>indices_index <span class="kw">in </span>increment_from..<span class="self">self</span>.indices.len() { |
| <span class="self">self</span>.indices[indices_index] = increment_value; |
| } |
| <span class="prelude-val">Some</span>(<span class="self">self</span>.current()) |
| } |
| <span class="comment">// Otherwise, we're done |
| </span><span class="prelude-val">None </span>=> <span class="prelude-val">None</span>, |
| } |
| } |
| } |
| |
| <span class="kw">impl</span><I> FusedIterator <span class="kw">for </span>CombinationsWithReplacement<I> |
| <span class="kw">where |
| </span>I: Iterator, |
| I::Item: Clone, |
| {} |
| </code></pre></div> |
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