---
layout: "default"
title: "Operator: prefix -"
description: "Swift documentation for the 'prefix -' operator."
root: "/v2.1"
---

<code class="language-swift">prefix operator prefix - {
    associativity 
    precedence 
}</code>

<h3>Declarations</h3>

<div class="declaration" id="func-mns_-double">
<a class="toggle-link" data-toggle="collapse" href="#comment-func-mns_-double">prefix func -(<wbr>_: Double)</a>
        
<div class="comment collapse" id="comment-func-mns_-double"><div class="p">
    

   