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<!doctype html><html lang=en class=no-js> <head><meta charset=utf-8><meta name=viewport content="width=device-width,initial-scale=1"><meta name=author content="Niels Lohmann"><link href="https://json.nlohmann.me/features/creating_values/" rel="canonical"><link href=../conversions/ rel=prev><link href=../element_access/ rel=next><link rel=icon href=../../assets/images/favicon.png><meta name=generator content="mkdocs-1.6.1, mkdocs-material-9.7.7"><title>Creating JSON values - JSON for Modern C++</title><link rel=stylesheet href=../../assets/stylesheets/main.ec1eaa64.min.css><link rel=stylesheet href=../../assets/stylesheets/palette.ab4e12ef.min.css><link rel="stylesheet" href="../../assets/external/fonts.googleapis.com/css.61a430c9.css"><style>:root{--md-text-font:"Roboto";--md-code-font:"JetBrains Mono"}</style><link rel=stylesheet href=../../css/custom.css><script>__md_scope=new 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<svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M12 8a3 3 0 0 0 3-3 3 3 0 0 0-3-3 3 3 0 0 0-3 3 3 3 0 0 0 3 3m0 3.54C9.64 9.35 6.5 8 3 8v11c3.5 0 6.64 1.35 9 3.54 2.36-2.19 5.5-3.54 9-3.54V8c-3.5 0-6.64 1.35-9 3.54"/></svg> </a> <label class="md-header__button md-icon" for=__drawer> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M3 6h18v2H3zm0 5h18v2H3zm0 5h18v2H3z"/></svg> </label> <div class=md-header__title data-md-component=header-title> <div class=md-header__ellipsis> <div class=md-header__topic> <span class=md-ellipsis> JSON for Modern C++ </span> </div> <div class=md-header__topic data-md-component=header-topic> <span class=md-ellipsis> Creating JSON values </span> </div> </div> </div> <form class=md-header__option data-md-component=palette> <input class=md-option data-md-color-media="(prefers-color-scheme: light)" data-md-color-scheme=default data-md-color-primary=indigo data-md-color-accent=indigo aria-label="Switch to dark mode" 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<!doctype html><html lang=en class=no-js> <head><meta charset=utf-8><meta name=viewport content="width=device-width,initial-scale=1"><meta name=author content="Niels Lohmann"><link href="https://json.nlohmann.me/features/creating_values/" rel="canonical"><link href=../conversions/ rel=prev><link href=../element_access/ rel=next><link rel=icon href=../../assets/images/favicon.png><meta name=generator content="mkdocs-1.6.1, mkdocs-material-9.7.7"><title>Creating JSON values - JSON for Modern C++</title><link rel=stylesheet href=../../assets/stylesheets/main.ec1eaa64.min.css><link rel=stylesheet href=../../assets/stylesheets/palette.ab4e12ef.min.css><link rel="stylesheet" href="../../assets/external/fonts.googleapis.com/css.61a430c9.css"><style>:root{--md-text-font:"Roboto";--md-code-font:"JetBrains Mono"}</style><link rel=stylesheet href=../../css/custom.css><script>__md_scope=new 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<svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M12 8a3 3 0 0 0 3-3 3 3 0 0 0-3-3 3 3 0 0 0-3 3 3 3 0 0 0 3 3m0 3.54C9.64 9.35 6.5 8 3 8v11c3.5 0 6.64 1.35 9 3.54 2.36-2.19 5.5-3.54 9-3.54V8c-3.5 0-6.64 1.35-9 3.54"/></svg> </a> <label class="md-header__button md-icon" for=__drawer> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M3 6h18v2H3zm0 5h18v2H3zm0 5h18v2H3z"/></svg> </label> <div class=md-header__title data-md-component=header-title> <div class=md-header__ellipsis> <div class=md-header__topic> <span class=md-ellipsis> JSON for Modern C++ </span> </div> <div class=md-header__topic data-md-component=header-topic> <span class=md-ellipsis> Creating JSON values </span> </div> </div> </div> <form class=md-header__option data-md-component=palette> <input class=md-option data-md-color-media="(prefers-color-scheme: light)" data-md-color-scheme=default data-md-color-primary=indigo data-md-color-accent=indigo aria-label="Switch to dark mode" 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12 4 15.31V20h4.69L12 23.31 15.31 20H20v-4.69L23.31 12z"/></svg> </label> </form> <script>var palette=__md_get("__palette");if(palette&&palette.color){if("(prefers-color-scheme)"===palette.color.media){var media=matchMedia("(prefers-color-scheme: light)"),input=document.querySelector(media.matches?"[data-md-color-media='(prefers-color-scheme: light)']":"[data-md-color-media='(prefers-color-scheme: dark)']");palette.color.media=input.getAttribute("data-md-color-media"),palette.color.scheme=input.getAttribute("data-md-color-scheme"),palette.color.primary=input.getAttribute("data-md-color-primary"),palette.color.accent=input.getAttribute("data-md-color-accent")}for(var[key,value]of Object.entries(palette.color))document.body.setAttribute("data-md-color-"+key,value)}</script> <label class="md-header__button md-icon" for=__search> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M9.5 3A6.5 6.5 0 0 1 16 9.5c0 1.61-.59 3.09-1.56 4.23l.27.27h.79l5 5-1.5 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<span class=n>json</span><span class=w> </span><span class=n>j_float</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=mf>3.141</span><span class=p>;</span>
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<span class=n>json</span><span class=w> </span><span class=n>j_string</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=s>"Hello"</span><span class=p>;</span>
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<span class=n>json</span><span class=w> </span><span class=n>j_boolean</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=nb>true</span><span class=p>;</span>
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@@ -21,7 +21,7 @@
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<span class=c1>// a JSON array with one object, not an object with one member</span>
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<span class=n>json</span><span class=w> </span><span class=n>array_of_objects</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>json</span><span class=o>::</span><span class=n>array</span><span class=p>({{</span><span class=s>"key"</span><span class=p>,</span><span class=w> </span><span class=s>"value"</span><span class=p>}});</span><span class=w> </span><span class=c1>// [{"key":"value"}]</span>
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</code></pre></div> <p>Related to this, single-element brace initialization such as <code class=highlight><span class=n>json</span><span class=w> </span><span class=n>j</span><span class=p>{</span><span class=n>value</span><span class=p>};</span></code> wraps the element in a single-element <strong>array</strong> by default, and its behavior even differs between compilers. See the <a href=../../home/faq/#brace-initialization-yields-arrays><abbr title="Frequently Asked Questions">FAQ</abbr></a> for details and the opt-in <a href=../../api/macros/json_brace_init_copy_semantics/ ><code>JSON_BRACE_INIT_COPY_SEMANTICS</code></a> macro.</p> </div> <h2 id=building-incrementally>Building incrementally<a class=headerlink href=#building-incrementally title="Permanent link">¶</a></h2> <p>A value can also be built up piece by piece. Accessing a non-existing object key or array index with <a href=../element_access/unchecked_access/ ><code>operator[]</code></a> creates the element on the fly:</p> <div class=highlight><pre><span></span><code><span class=n>json</span><span class=w> </span><span class=n>j</span><span class=p>;</span><span class=w> </span><span class=c1>// null</span>
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</code></pre></div> <p>Related to this, single-element brace initialization such as <code class=highlight><span class=n>json</span><span class=w> </span><span class=n>j</span><span class=p>{</span><span class=n>value</span><span class=p>};</span></code> wraps the element in a single-element <strong>array</strong> by default, and its behavior even differs between compilers. See the <a href=../../home/faq/#brace-initialization-yields-arrays><abbr title="Frequently Asked Questions">FAQ</abbr></a> for details and the opt-in <a href=../../api/macros/json_brace_init_copy_semantics/ ><code>JSON_BRACE_INIT_COPY_SEMANTICS</code></a> macro.</p> </div> <h3 id=what-does-this-produce>What does this produce?<a class=headerlink href=#what-does-this-produce title="Permanent link">¶</a></h3> <p>The following table shows how some common spellings are interpreted. When in doubt, use <code class=highlight><span class=n>json</span><span class=o>::</span><span class=n>array</span><span class=p>()</span></code>, <code class=highlight><span class=n>json</span><span class=o>::</span><span class=n>object</span><span class=p>()</span></code>, or the <code class=highlight><span class=n>json</span><span class=p>(</span><span class=n>value</span><span class=p>)</span></code> form with parentheses.</p> <table> <thead> <tr> <th>code</th> <th>result</th> <th>note</th> </tr> </thead> <tbody> <tr> <td><code class=highlight><span class=n>json</span><span class=w> </span><span class=n>j</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=p>{};</span></code> / <code class=highlight><span class=n>json</span><span class=w> </span><span class=n>j</span><span class=p>{};</span></code></td> <td><code class=highlight><span class=kc>null</span></code></td> <td>use <code>json::object()</code> or <code>json::array()</code></td> </tr> <tr> <td><code class=highlight><span class=n>json</span><span class=w> </span><span class=n>j</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>json</span><span class=o>::</span><span class=n>object</span><span class=p>();</span></code></td> <td><code class=highlight><span class=p>{}</span></code></td> <td></td> </tr> <tr> <td><code class=highlight><span class=n>json</span><span class=w> </span><span class=n>j</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>json</span><span class=o>::</span><span class=n>array</span><span class=p>();</span></code></td> <td><code class=highlight><span class=p>[]</span></code></td> <td></td> </tr> <tr> <td><code class=highlight><span class=n>json</span><span class=w> </span><span class=nf>j</span><span class=p>(</span><span class=nb>true</span><span class=p>);</span></code></td> <td><code class=highlight><span class=kc>true</span></code></td> <td>parentheses create the value itself</td> </tr> <tr> <td><code class=highlight><span class=n>json</span><span class=w> </span><span class=n>j</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=p>{</span><span class=nb>true</span><span class=p>};</span></code></td> <td><code class=highlight><span class=p>[</span><span class=kc>true</span><span class=p>]</span></code></td> <td>braces create a one-element array (<code class=highlight><span class=n>json</span><span class=w> </span><span class=n>j</span><span class=p>{</span><span class=nb>true</span><span class=p>};</span></code> depends on the compiler, see the <a href=../../home/faq/#brace-initialization-yields-arrays><abbr title="Frequently Asked Questions">FAQ</abbr></a>)</td> </tr> <tr> <td><code class=highlight><span class=n>json</span><span class=w> </span><span class=n>j</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=p>{{</span><span class=s>"a"</span><span class=p>,</span><span class=w> </span><span class=mi>1</span><span class=p>}};</span></code></td> <td><code class=highlight><span class=p>{</span><span class=nt>"a"</span><span class=p>:</span><span class=mi>1</span><span class=p>}</span></code></td> <td>all elements are <code>[string, value]</code> pairs: object</td> </tr> <tr> <td><code class=highlight><span class=n>json</span><span class=w> </span><span class=n>j</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=p>{{</span><span class=s>"a"</span><span class=p>,</span><span class=w> </span><span class=mi>1</span><span class=p>},</span><span class=w> </span><span class=p>{</span><span class=s>"b"</span><span class=p>}};</span></code></td> <td><code class=highlight><span class=p>[[</span><span class=s2>"a"</span><span class=p>,</span><span class=mi>1</span><span class=p>],[</span><span class=s2>"b"</span><span class=p>]]</span></code></td> <td>one element is not a pair: array</td> </tr> <tr> <td><code class=highlight><span class=n>json</span><span class=w> </span><span class=n>j</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=p>{{</span><span claLine truncated
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||||
<span class=n>j</span><span class=p>[</span><span class=s>"answer"</span><span class=p>][</span><span class=s>"everything"</span><span class=p>]</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=mi>42</span><span class=p>;</span><span class=w> </span><span class=c1>// becomes an object</span>
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<span class=n>j</span><span class=p>[</span><span class=s>"list"</span><span class=p>]</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=p>{</span><span class=mi>1</span><span class=p>,</span><span class=w> </span><span class=mi>0</span><span class=p>,</span><span class=w> </span><span class=mi>2</span><span class=p>};</span>
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<span class=n>j</span><span class=p>[</span><span class=s>"list"</span><span class=p>].</span><span class=n>push_back</span><span class=p>(</span><span class=mi>3</span><span class=p>);</span><span class=w> </span><span class=c1>// [1,0,2,3]</span>
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@@ -29,7 +29,7 @@
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<span class=cp>#include</span><span class=w> </span><span class=cpf><iomanip></span>
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<span class=cp>#include</span><span class=w> </span><span class=cpf><nlohmann/json.hpp></span>
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<span class=k>using</span><span class=w> </span><span class=n>json</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>nlohmann</span><span class=o>::</span><span class=n>json</span><span class=p>;</span>
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<span class=k>using</span><span class=w> </span><span class=n>nlohmann</span><span class=o>::</span><span class=n>json</span><span class=p>;</span>
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<span class=k>using</span><span class=w> </span><span class=k>namespace</span><span class=w> </span><span class=nn>nlohmann</span><span class=o>::</span><span class=nn>literals</span><span class=p>;</span>
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<span class=kt>int</span><span class=w> </span><span class=nf>main</span><span class=p>()</span>
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@@ -42,4 +42,4 @@
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<span class=w> </span><span class=nt>"answer"</span><span class=p>:</span><span class=w> </span><span class=mi>42</span><span class=p>,</span>
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<span class=w> </span><span class=nt>"hello"</span><span class=p>:</span><span class=w> </span><span class=s2>"world"</span>
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<span class=p>}</span>
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||||
</code></pre></div> </details> <p>Note this <strong>parses</strong> the string, so <code class=highlight><span class=s>"42"</span><span class=n>_json</span></code> is the number <code class=highlight><span class=mi>42</span></code>, whereas <code class=highlight><span class=n>json</span><span class=p>(</span><span class=s>"42"</span><span class=p>)</span></code> is the <abbr title="JavaScript Object Notation">JSON</abbr> string <code class=highlight><span class=s2>"42"</span></code>.</p> <h2 id=see-also>See also<a class=headerlink href=#see-also title="Permanent link">¶</a></h2> <ul> <li><a href=../../api/basic_json/basic_json/ ><code>basic_json</code> constructors</a> - all ways to construct a value</li> <li><a href=../../api/basic_json/array/ ><code>array</code></a> / <a href=../../api/basic_json/object/ ><code>object</code></a> - force array or object type</li> <li><a href=../../api/operator_literal_json/ ><code>operator""_json</code></a> - the <code>_json</code> literal</li> <li><a href=../conversions/ >Converting values</a> - which C++ types can be used</li> <li><a href=../parsing/ >Parsing</a> - create a value from <abbr title="JavaScript Object Notation">JSON</abbr> text</li> <li><a href=../json_view/ >Zero-copy <abbr title="JavaScript Object Notation">JSON</abbr> views</a> - create a document and a view from <abbr title="JavaScript Object Notation">JSON</abbr> text instead of a value</li> </ul> <!-- https://squidfunk.github.io/mkdocs-material/reference/tooltips/#adding-a-glossary --> <aside class=md-source-file> <span class=md-source-file__fact> <span class=md-icon title="Last update"> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M21 13.1c-.1 0-.3.1-.4.2l-1 1 2.1 2.1 1-1c.2-.2.2-.6 0-.8l-1.3-1.3c-.1-.1-.2-.2-.4-.2m-1.9 1.8-6.1 6V23h2.1l6.1-6.1zM12.5 7v5.2l4 2.4-1 1L11 13V7zM11 21.9c-5.1-.5-9-4.8-9-9.9C2 6.5 6.5 2 12 2c5.3 0 9.6 4.1 10 9.3-.3-.1-.6-.2-1-.2s-.7.1-1 .2C19.6 7.2 16.2 4 12 4c-4.4 0-8 3.6-8 8 0 4.1 3.1 7.5 7.1 7.9l-.1.2z"/></svg> </span> <span class="git-revision-date-localized-plugin git-revision-date-localized-plugin-date" title="October 25, 2026 05:18:07 UTC">October 25, 2026</span> </span> </aside> </article> </div> <script>var tabs=__md_get("__tabs");if(Array.isArray(tabs))e:for(var set of document.querySelectorAll(".tabbed-set")){var labels=set.querySelector(".tabbed-labels");for(var tab of tabs)for(var label of labels.getElementsByTagName("label"))if(label.innerText.trim()===tab){var input=document.getElementById(label.htmlFor);input.checked=!0;continue e}}</script> <script>var target=document.getElementById(location.hash.slice(1));target&&target.name&&(target.checked=target.name.startsWith("__tabbed_"))</script> </div> <button type=button class="md-top md-icon" data-md-component=top hidden> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M13 20h-2V8l-5.5 5.5-1.42-1.42L12 4.16l7.92 7.92-1.42 1.42L13 8z"/></svg> Back to top </button> </main> <footer class=md-footer> <div class="md-footer-meta md-typeset"> <div class="md-footer-meta__inner md-grid"> <div class=md-copyright> <div class=md-copyright__highlight> Copyright © 2013-2026 Niels Lohmann </div> </div> <div class=md-social> <a href="https://github.com/nlohmann" target="_blank" rel="noopener" title="github.com" class="md-social__link"> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 512 512"><!-- Font Awesome Free 7.1.0 by @fontawesome - 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||||
</code></pre></div> </details> <p>Note this <strong>parses</strong> the string, so <code class=highlight><span class=s>"42"</span><span class=n>_json</span></code> is the number <code class=highlight><span class=mi>42</span></code>, whereas <code class=highlight><span class=n>json</span><span class=p>(</span><span class=s>"42"</span><span class=p>)</span></code> is the <abbr title="JavaScript Object Notation">JSON</abbr> string <code class=highlight><span class=s2>"42"</span></code>.</p> <h2 id=see-also>See also<a class=headerlink href=#see-also title="Permanent link">¶</a></h2> <ul> <li><a href=../../api/basic_json/basic_json/ ><code>basic_json</code> constructors</a> - all ways to construct a value</li> <li><a href=../../api/basic_json/array/ ><code>array</code></a> / <a href=../../api/basic_json/object/ ><code>object</code></a> - force array or object type</li> <li><a href=../../api/operator_literal_json/ ><code>operator""_json</code></a> - the <code>_json</code> literal</li> <li><a href=../conversions/ >Converting values</a> - which C++ types can be used</li> <li><a href=../parsing/ >Parsing</a> - create a value from <abbr title="JavaScript Object Notation">JSON</abbr> text</li> <li><a href=../json_view/ >Zero-copy <abbr title="JavaScript Object Notation">JSON</abbr> views</a> - create a document and a view from <abbr title="JavaScript Object Notation">JSON</abbr> text instead of a value</li> </ul> <!-- https://squidfunk.github.io/mkdocs-material/reference/tooltips/#adding-a-glossary --> <aside class=md-source-file> <span class=md-source-file__fact> <span class=md-icon title="Last update"> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M21 13.1c-.1 0-.3.1-.4.2l-1 1 2.1 2.1 1-1c.2-.2.2-.6 0-.8l-1.3-1.3c-.1-.1-.2-.2-.4-.2m-1.9 1.8-6.1 6V23h2.1l6.1-6.1zM12.5 7v5.2l4 2.4-1 1L11 13V7zM11 21.9c-5.1-.5-9-4.8-9-9.9C2 6.5 6.5 2 12 2c5.3 0 9.6 4.1 10 9.3-.3-.1-.6-.2-1-.2s-.7.1-1 .2C19.6 7.2 16.2 4 12 4c-4.4 0-8 3.6-8 8 0 4.1 3.1 7.5 7.1 7.9l-.1.2z"/></svg> </span> <span class="git-revision-date-localized-plugin git-revision-date-localized-plugin-date" title="October 25, 2026 11:07:13 UTC">October 25, 2026</span> </span> </aside> </article> </div> <script>var tabs=__md_get("__tabs");if(Array.isArray(tabs))e:for(var set of document.querySelectorAll(".tabbed-set")){var labels=set.querySelector(".tabbed-labels");for(var tab of tabs)for(var label of labels.getElementsByTagName("label"))if(label.innerText.trim()===tab){var input=document.getElementById(label.htmlFor);input.checked=!0;continue e}}</script> <script>var target=document.getElementById(location.hash.slice(1));target&&target.name&&(target.checked=target.name.startsWith("__tabbed_"))</script> </div> <button type=button class="md-top md-icon" data-md-component=top hidden> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M13 20h-2V8l-5.5 5.5-1.42-1.42L12 4.16l7.92 7.92-1.42 1.42L13 8z"/></svg> Back to top </button> </main> <footer class=md-footer> <div class="md-footer-meta md-typeset"> <div class="md-footer-meta__inner md-grid"> <div class=md-copyright> <div class=md-copyright__highlight> Copyright © 2013-2026 Niels Lohmann </div> </div> <div class=md-social> <a href="https://github.com/nlohmann" target="_blank" rel="noopener" title="github.com" class="md-social__link"> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 512 512"><!-- Font Awesome Free 7.1.0 by @fontawesome - 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|
||||
@@ -52,6 +52,24 @@ json array_of_objects = json::array({{"key", "value"}}); // [{"key":"value"}]
|
||||
|
||||
Related to this, single-element brace initialization such as `json j{value};` wraps the element in a single-element **array** by default, and its behavior even differs between compilers. See the [FAQ](https://json.nlohmann.me/home/faq/#brace-initialization-yields-arrays) for details and the opt-in [`JSON_BRACE_INIT_COPY_SEMANTICS`](https://json.nlohmann.me/api/macros/json_brace_init_copy_semantics/index.md) macro.
|
||||
|
||||
### What does this produce?
|
||||
|
||||
The following table shows how some common spellings are interpreted. When in doubt, use `json::array()`, `json::object()`, or the `json(value)` form with parentheses.
|
||||
|
||||
| code | result | note |
|
||||
| ------------------------------------ | ----------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------- |
|
||||
| `json j = {};` / `json j{};` | `null` | use `json::object()` or `json::array()` |
|
||||
| `json j = json::object();` | `{}` | |
|
||||
| `json j = json::array();` | `[]` | |
|
||||
| `json j(true);` | `true` | parentheses create the value itself |
|
||||
| `json j = {true};` | `[true]` | braces create a one-element array (`json j{true};` depends on the compiler, see the [FAQ](https://json.nlohmann.me/home/faq/#brace-initialization-yields-arrays)) |
|
||||
| `json j = {{"a", 1}};` | `{"a":1}` | all elements are `[string, value]` pairs: object |
|
||||
| `json j = {{"a", 1}, {"b"}};` | `[["a",1],["b"]]` | one element is not a pair: array |
|
||||
| `json j = {{"a", 1}, 2};` | `[["a",1],2]` | a plain value among pairs: array |
|
||||
| `json j = {{"a", 1, 2}};` | `[["a",1,2]]` | a three-element list is not a pair: array |
|
||||
| `json j = "{\"a\":1}";` | `"{\"a\":1}"` | a string **value**; it is not parsed |
|
||||
| `json j = json::parse("{\"a\":1}");` | `{"a":1}` | parse text with `parse` or `_json` |
|
||||
|
||||
## Building incrementally
|
||||
|
||||
A value can also be built up piece by piece. Accessing a non-existing object key or array index with [`operator[]`](https://json.nlohmann.me/features/element_access/unchecked_access/index.md) creates the element on the fly:
|
||||
@@ -76,7 +94,7 @@ Example
|
||||
#include <iomanip>
|
||||
#include <nlohmann/json.hpp>
|
||||
|
||||
using json = nlohmann::json;
|
||||
using nlohmann::json;
|
||||
using namespace nlohmann::literals;
|
||||
|
||||
int main()
|
||||
|
||||
Reference in new issue
Block a user