<main><divclass="width-limiter"><navclass="sub"><formclass="search-form"><span></span><divid="sidebar-button"tabindex="-1"><ahref="../itertools/all.html"title="show sidebar"></a></div><inputclass="search-input"name="search"aria-label="Run search in the documentation"autocomplete="off"spellcheck="false"placeholder="Click or press ‘S’ to search, ‘?’ for more options…"type="search"><divid="help-button"tabindex="-1"><ahref="../help.html"title="help">?</a></div><divid="settings-menu"tabindex="-1"><ahref="../settings.html"title="settings"><imgwidth="22"height="22"alt="Change settings"src="../static.files/wheel-7b819b6101059cd0.svg"></a></div></form></nav><sectionid="main-content"class="content"><divclass="main-heading"><h1>Function <ahref="index.html">itertools</a>::<wbr><aclass="fn"href="#">fold</a><buttonid="copy-path"title="Copy item path to clipboard"><imgsrc="../static.files/clipboard-7571035ce49a181d.svg"width="19"height="18"alt="Copy item path"></button></h1><spanclass="out-of-band"><aclass="src"href="../src/itertools/free.rs.html#186-192">source</a> · <buttonid="toggle-all-docs"title="collapse all docs">[<span>−</span>]</button></span></div><preclass="rust item-decl"><code>pub fn fold<I, B, F>(iterable: I, init: B, f: F) -> B<divclass="where">where
F: <aclass="trait"href="https://doc.rust-lang.org/1.78.0/core/ops/function/trait.FnMut.html"title="trait core::ops::function::FnMut">FnMut</a>(B, I::<aclass="associatedtype"href="https://doc.rust-lang.org/1.78.0/core/iter/traits/collect/trait.IntoIterator.html#associatedtype.Item"title="type core::iter::traits::collect::IntoIterator::Item">Item</a>) -> B,</div></code></pre><detailsclass="toggle top-doc"open><summaryclass="hideme"><span>Expand description</span></summary><divclass="docblock"><p>Perform a fold operation over the iterable.</p>
<p><ahref="https://doc.rust-lang.org/1.78.0/core/iter/traits/collect/trait.IntoIterator.html"title="trait core::iter::traits::collect::IntoIterator"><code>IntoIterator</code></a> enabled version of <ahref="https://doc.rust-lang.org/1.78.0/core/iter/traits/iterator/trait.Iterator.html#method.fold"title="method core::iter::traits::iterator::Iterator::fold"><code>Iterator::fold</code></a>.</p>