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<div class="refnamediv">
<h1 class="refname">json_encode</h1>
<p class="verinfo">(PHP 5 >= 5.2.0, PECL json >= 1.2.0)</p><p class="refpurpose"><span class="refname">json_encode</span> — <span class="dc-title">Returns the JSON representation of a value</span></p>
</div>
<div class="refsect1 description" id="refsect1-function.json-encode-description">
<h3 class="title">Description</h3>
<div class="methodsynopsis dc-description">
<span class="type">string</span> <span class="methodname"><strong>json_encode</strong></span>
( <span class="methodparam"><span class="type"><a href="language.pseudo-types.html#language.types.mixed" class="type mixed">mixed</a></span> <code class="parameter">$value</code></span>
[, <span class="methodparam"><span class="type">int</span> <code class="parameter">$options</code><span class="initializer"> = 0</span></span>
[, <span class="methodparam"><span class="type">int</span> <code class="parameter">$depth</code><span class="initializer"> = 512</span></span>
]] )</div>
<p class="para rdfs-comment">
Returns a string containing the JSON representation of
<em><code class="parameter">value</code></em>.
</p>
</div>
<div class="refsect1 parameters" id="refsect1-function.json-encode-parameters">
<h3 class="title">Parameters</h3>
<p class="para">
<dl>
<dt>
<span class="term"><em><code class="parameter">value</code></em></span>
<dd>
<p class="para">
The <em><code class="parameter">value</code></em> being encoded. Can be any type except
a <span class="type"><a href="language.types.resource.html" class="type resource">resource</a></span>.
</p>
<p class="para">
All string data must be UTF-8 encoded.
</p>
<blockquote class="note"><p><strong class="note">Note</strong>: <p class="para">PHP implements a superset of
JSON - it will also encode and decode scalar types and <strong><code>NULL</code></strong>. The JSON standard
only supports these values when they are nested inside an array or an object.
</p></p></blockquote>
</dd>
</dt>
<dt>
<span class="term"><em><code class="parameter">options</code></em></span>
<dd>
<p class="para">
Bitmask consisting of <strong><code>JSON_HEX_QUOT</code></strong>,
<strong><code>JSON_HEX_TAG</code></strong>,
<strong><code>JSON_HEX_AMP</code></strong>,
<strong><code>JSON_HEX_APOS</code></strong>,
<strong><code>JSON_NUMERIC_CHECK</code></strong>,
<strong><code>JSON_PRETTY_PRINT</code></strong>,
<strong><code>JSON_UNESCAPED_SLASHES</code></strong>,
<strong><code>JSON_FORCE_OBJECT</code></strong>,
<strong><code>JSON_UNESCAPED_UNICODE</code></strong>. The behaviour of these
constants is described on
<a href="json.constants.html" class="link">the JSON constants page</a>.
</p>
</dd>
</dt>
<dt>
<span class="term"><em><code class="parameter">depth</code></em></span>
<dd>
<p class="para">
Set the maximum depth. Must be greater than zero.
</p>
</dd>
</dt>
</dl>
</p>
</div>
<div class="refsect1 returnvalues" id="refsect1-function.json-encode-returnvalues">
<h3 class="title">Return Values</h3>
<p class="para">
Returns a JSON encoded <span class="type"><a href="language.types.string.html" class="type string">string</a></span> on success or <strong><code>FALSE</code></strong> on failure.
</p>
</div>
<div class="refsect1 changelog" id="refsect1-function.json-encode-changelog">
<h3 class="title">Changelog</h3>
<p class="para">
<table class="doctable informaltable">
<thead>
<tr>
<th>Version</th>
<th>Description</th>
</tr>
</thead>
<tbody class="tbody">
<tr>
<td>5.5.0</td>
<td>
<em><code class="parameter">depth</code></em> parameter was added.
</td>
</tr>
<tr>
<td>5.4.0</td>
<td>
<strong><code>JSON_PRETTY_PRINT</code></strong>, <strong><code>JSON_UNESCAPED_SLASHES</code></strong>, and <strong><code>JSON_UNESCAPED_UNICODE</code></strong> <em><code class="parameter">options</code></em> were added.
</td>
</tr>
<tr>
<td>5.3.3</td>
<td>
<strong><code>JSON_NUMERIC_CHECK</code></strong> <em><code class="parameter">option</code></em> was added.
</td>
</tr>
<tr>
<td>5.3.0</td>
<td>
The <em><code class="parameter">options</code></em> parameter was added.
</td>
</tr>
</tbody>
</table>
</p>
</div>
<div class="refsect1 examples" id="refsect1-function.json-encode-examples">
<h3 class="title">Examples</h3>
<p class="para">
<div class="example" id="example-3760">
<p><strong>Example #1 A <span class="function"><strong>json_encode()</strong></span> example</strong></p>
<div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br />$arr </span><span style="color: #007700">= array(</span><span style="color: #DD0000">'a' </span><span style="color: #007700">=> </span><span style="color: #0000BB">1</span><span style="color: #007700">, </span><span style="color: #DD0000">'b' </span><span style="color: #007700">=> </span><span style="color: #0000BB">2</span><span style="color: #007700">, </span><span style="color: #DD0000">'c' </span><span style="color: #007700">=> </span><span style="color: #0000BB">3</span><span style="color: #007700">, </span><span style="color: #DD0000">'d' </span><span style="color: #007700">=> </span><span style="color: #0000BB">4</span><span style="color: #007700">, </span><span style="color: #DD0000">'e' </span><span style="color: #007700">=> </span><span style="color: #0000BB">5</span><span style="color: #007700">);<br /><br />echo </span><span style="color: #0000BB">json_encode</span><span style="color: #007700">(</span><span style="color: #0000BB">$arr</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">?></span>
</span>
</code></div>
</div>
<div class="example-contents"><p>The above example will output:</p></div>
<div class="example-contents screen">
<div class="cdata"><pre>
{"a":1,"b":2,"c":3,"d":4,"e":5}
</pre></div>
</div>
</div>
<div class="example" id="example-3761">
<p><strong>Example #2
A <span class="function"><strong>json_encode()</strong></span> example showing some options in use
</strong></p>
<div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br />$a </span><span style="color: #007700">= array(</span><span style="color: #DD0000">'<foo>'</span><span style="color: #007700">,</span><span style="color: #DD0000">"'bar'"</span><span style="color: #007700">,</span><span style="color: #DD0000">'"baz"'</span><span style="color: #007700">,</span><span style="color: #DD0000">'&blong&'</span><span style="color: #007700">, </span><span style="color: #DD0000">"\xc3\xa9"</span><span style="color: #007700">);<br /><br />echo </span><span style="color: #DD0000">"Normal: "</span><span style="color: #007700">, </span><span style="color: #0000BB">json_encode</span><span style="color: #007700">(</span><span style="color: #0000BB">$a</span><span style="color: #007700">), </span><span style="color: #DD0000">"\n"</span><span style="color: #007700">;<br />echo </span><span style="color: #DD0000">"Tags: "</span><span style="color: #007700">, </span><span style="color: #0000BB">json_encode</span><span style="color: #007700">(</span><span style="color: #0000BB">$a</span><span style="color: #007700">, </span><span style="color: #0000BB">JSON_HEX_TAG</span><span style="color: #007700">), </span><span style="color: #DD0000">"\n"</span><span style="color: #007700">;<br />echo </span><span style="color: #DD0000">"Apos: "</span><span style="color: #007700">, </span><span style="color: #0000BB">json_encode</span><span style="color: #007700">(</span><span style="color: #0000BB">$a</span><span style="color: #007700">, </span><span style="color: #0000BB">JSON_HEX_APOS</span><span style="color: #007700">), </span><span style="color: #DD0000">"\n"</span><span style="color: #007700">;<br />echo </span><span style="color: #DD0000">"Quot: "</span><span style="color: #007700">, </span><span style="color: #0000BB">json_encode</span><span style="color: #007700">(</span><span style="color: #0000BB">$a</span><span style="color: #007700">, </span><span style="color: #0000BB">JSON_HEX_QUOT</span><span style="color: #007700">), </span><span style="color: #DD0000">"\n"</span><span style="color: #007700">;<br />echo </span><span style="color: #DD0000">"Amp: "</span><span style="color: #007700">, </span><span style="color: #0000BB">json_encode</span><span style="color: #007700">(</span><span style="color: #0000BB">$a</span><span style="color: #007700">, </span><span style="color: #0000BB">JSON_HEX_AMP</span><span style="color: #007700">), </span><span style="color: #DD0000">"\n"</span><span style="color: #007700">;<br />echo </span><span style="color: #DD0000">"Unicode: "</span><span style="color: #007700">, </span><span style="color: #0000BB">json_encode</span><span style="color: #007700">(</span><span style="color: #0000BB">$a</span><span style="color: #007700">, </span><span style="color: #0000BB">JSON_UNESCAPED_UNICODE</span><span style="color: #007700">), </span><span style="color: #DD0000">"\n"</span><span style="color: #007700">;<br />echo </span><span style="color: #DD0000">"All: "</span><span style="color: #007700">, </span><span style="color: #0000BB">json_encode</span><span style="color: #007700">(</span><span style="color: #0000BB">$a</span><span style="color: #007700">, </span><span style="color: #0000BB">JSON_HEX_TAG </span><span style="color: #007700">| </span><span style="color: #0000BB">JSON_HEX_APOS </span><span style="color: #007700">| </span><span style="color: #0000BB">JSON_HEX_QUOT </span><span style="color: #007700">| </span><span style="color: #0000BB">JSON_HEX_AMP </span><span style="color: #007700">| </span><span style="color: #0000BB">JSON_UNESCAPED_UNICODE</span><span style="color: #007700">), </span><span style="color: #DD0000">"\n\n"</span><span style="color: #007700">;<br /><br /></span><span style="color: #0000BB">$b </span><span style="color: #007700">= array();<br /><br />echo </span><span style="color: #DD0000">"Empty array output as array: "</span><span style="color: #007700">, </span><span style="color: #0000BB">json_encode</span><span style="color: #007700">(</span><span style="color: #0000BB">$b</span><span style="color: #007700">), </span><span style="color: #DD0000">"\n"</span><span style="color: #007700">;<br />echo </span><span style="color: #DD0000">"Empty array output as object: "</span><span style="color: #007700">, </span><span style="color: #0000BB">json_encode</span><span style="color: #007700">(</span><span style="color: #0000BB">$b</span><span style="color: #007700">, </span><span style="color: #0000BB">JSON_FORCE_OBJECT</span><span style="color: #007700">), </span><span style="color: #DD0000">"\n\n"</span><span style="color: #007700">;<br /><br /></span><span style="color: #0000BB">$c </span><span style="color: #007700">= array(array(</span><span style="color: #0000BB">1</span><span style="color: #007700">,</span><span style="color: #0000BB">2</span><span style="color: #007700">,</span><span style="color: #0000BB">3</span><span style="color: #007700">));<br /><br />echo </span><span style="color: #DD0000">"Non-associative array output as array: "</span><span style="color: #007700">, </span><span style="color: #0000BB">json_encode</span><span style="color: #007700">(</span><span style="color: #0000BB">$c</span><span style="color: #007700">), </span><span style="color: #DD0000">"\n"</span><span style="color: #007700">;<br />echo </span><span style="color: #DD0000">"Non-associative array output as object: "</span><span style="color: #007700">, </span><span style="color: #0000BB">json_encode</span><span style="color: #007700">(</span><span style="color: #0000BB">$c</span><span style="color: #007700">, </span><span style="color: #0000BB">JSON_FORCE_OBJECT</span><span style="color: #007700">), </span><span style="color: #DD0000">"\n\n"</span><span style="color: #007700">;<br /><br /></span><span style="color: #0000BB">$d </span><span style="color: #007700">= array(</span><span style="color: #DD0000">'foo' </span><span style="color: #007700">=> </span><span style="color: #DD0000">'bar'</span><span style="color: #007700">, </span><span style="color: #DD0000">'baz' </span><span style="color: #007700">=> </span><span style="color: #DD0000">'long'</span><span style="color: #007700">);<br /><br />echo </span><span style="color: #DD0000">"Associative array always output as object: "</span><span style="color: #007700">, </span><span style="color: #0000BB">json_encode</span><span style="color: #007700">(</span><span style="color: #0000BB">$d</span><span style="color: #007700">), </span><span style="color: #DD0000">"\n"</span><span style="color: #007700">;<br />echo </span><span style="color: #DD0000">"Associative array always output as object: "</span><span style="color: #007700">, </span><span style="color: #0000BB">json_encode</span><span style="color: #007700">(</span><span style="color: #0000BB">$d</span><span style="color: #007700">, </span><span style="color: #0000BB">JSON_FORCE_OBJECT</span><span style="color: #007700">), </span><span style="color: #DD0000">"\n\n"</span><span style="color: #007700">;<br /></span><span style="color: #0000BB">?></span>
</span>
</code></div>
</div>
<div class="example-contents"><p>The above example will output:</p></div>
<div class="example-contents screen">
<div class="cdata"><pre>
Normal: ["<foo>","'bar'","\"baz\"","&blong&","\u00e9"]
Tags: ["\u003Cfoo\u003E","'bar'","\"baz\"","&blong&","\u00e9"]
Apos: ["<foo>","\u0027bar\u0027","\"baz\"","&blong&","\u00e9"]
Quot: ["<foo>","'bar'","\u0022baz\u0022","&blong&","\u00e9"]
Amp: ["<foo>","'bar'","\"baz\"","\u0026blong\u0026","\u00e9"]
Unicode: ["<foo>","'bar'","\"baz\"","&blong&","é"]
All: ["\u003Cfoo\u003E","\u0027bar\u0027","\u0022baz\u0022","\u0026blong\u0026","é"]
Empty array output as array: []
Empty array output as object: {}
Non-associative array output as array: [[1,2,3]]
Non-associative array output as object: {"0":{"0":1,"1":2,"2":3}}
Associative array always output as object: {"foo":"bar","baz":"long"}
Associative array always output as object: {"foo":"bar","baz":"long"}
</pre></div>
</div>
</div>
<div class="example" id="example-3762">
<p><strong>Example #3 Sequential versus non-sequential array example</strong></p>
<div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br /></span><span style="color: #007700">echo </span><span style="color: #DD0000">"Sequential array"</span><span style="color: #007700">.</span><span style="color: #0000BB">PHP_EOL</span><span style="color: #007700">;<br /></span><span style="color: #0000BB">$sequential </span><span style="color: #007700">= array(</span><span style="color: #DD0000">"foo"</span><span style="color: #007700">, </span><span style="color: #DD0000">"bar"</span><span style="color: #007700">, </span><span style="color: #DD0000">"baz"</span><span style="color: #007700">, </span><span style="color: #DD0000">"blong"</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">var_dump</span><span style="color: #007700">(<br /> </span><span style="color: #0000BB">$sequential</span><span style="color: #007700">,<br /> </span><span style="color: #0000BB">json_encode</span><span style="color: #007700">(</span><span style="color: #0000BB">$sequential</span><span style="color: #007700">)<br />);<br /><br />echo </span><span style="color: #0000BB">PHP_EOL</span><span style="color: #007700">.</span><span style="color: #DD0000">"Non-sequential array"</span><span style="color: #007700">.</span><span style="color: #0000BB">PHP_EOL</span><span style="color: #007700">;<br /></span><span style="color: #0000BB">$nonsequential </span><span style="color: #007700">= array(</span><span style="color: #0000BB">1</span><span style="color: #007700">=></span><span style="color: #DD0000">"foo"</span><span style="color: #007700">, </span><span style="color: #0000BB">2</span><span style="color: #007700">=></span><span style="color: #DD0000">"bar"</span><span style="color: #007700">, </span><span style="color: #0000BB">3</span><span style="color: #007700">=></span><span style="color: #DD0000">"baz"</span><span style="color: #007700">, </span><span style="color: #0000BB">4</span><span style="color: #007700">=></span><span style="color: #DD0000">"blong"</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">var_dump</span><span style="color: #007700">(<br /> </span><span style="color: #0000BB">$nonsequential</span><span style="color: #007700">,<br /> </span><span style="color: #0000BB">json_encode</span><span style="color: #007700">(</span><span style="color: #0000BB">$nonsequential</span><span style="color: #007700">)<br />);<br /><br />echo </span><span style="color: #0000BB">PHP_EOL</span><span style="color: #007700">.</span><span style="color: #DD0000">"Sequential array with one key unset"</span><span style="color: #007700">.</span><span style="color: #0000BB">PHP_EOL</span><span style="color: #007700">;<br />unset(</span><span style="color: #0000BB">$sequential</span><span style="color: #007700">[</span><span style="color: #0000BB">1</span><span style="color: #007700">]);<br /></span><span style="color: #0000BB">var_dump</span><span style="color: #007700">(<br /> </span><span style="color: #0000BB">$sequential</span><span style="color: #007700">,<br /> </span><span style="color: #0000BB">json_encode</span><span style="color: #007700">(</span><span style="color: #0000BB">$sequential</span><span style="color: #007700">)<br />);<br /></span><span style="color: #0000BB">?></span>
</span>
</code></div>
</div>
<div class="example-contents"><p>The above example will output:</p></div>
<div class="example-contents screen">
<div class="cdata"><pre>
Sequential array
array(4) {
[0]=>
string(3) "foo"
[1]=>
string(3) "bar"
[2]=>
string(3) "baz"
[3]=>
string(5) "blong"
}
string(27) "["foo","bar","baz","blong"]"
Non-sequential array
array(4) {
[1]=>
string(3) "foo"
[2]=>
string(3) "bar"
[3]=>
string(3) "baz"
[4]=>
string(5) "blong"
}
string(43) "{"1":"foo","2":"bar","3":"baz","4":"blong"}"
Sequential array with one key unset
array(3) {
[0]=>
string(3) "foo"
[2]=>
string(3) "baz"
[3]=>
string(5) "blong"
}
string(33) "{"0":"foo","2":"baz","3":"blong"}"
</pre></div>
</div>
</div>
</p>
</div>
<div class="refsect1 notes" id="refsect1-function.json-encode-notes">
<h3 class="title">Notes</h3>
<blockquote class="note"><p><strong class="note">Note</strong>:
<p class="para">
In the event of a failure to encode, <span class="function"><a href="function.json-last-error.html" class="function">json_last_error()</a></span>
can be used to determine the exact nature of the error.
</p>
</p></blockquote>
<blockquote class="note"><p><strong class="note">Note</strong>:
<p class="para">
When encoding an array, if the keys are not a continuous numeric
sequence starting from 0, all keys are encoded as strings, and
specified explicitly for each key-value pair.
</p>
</p></blockquote>
<blockquote class="note"><p><strong class="note">Note</strong>:
<p class="para">
Like the reference JSON encoder, <span class="function"><strong>json_encode()</strong></span> will
generate JSON that is a simple value (that is, neither an object nor an
array) if given a <span class="type"><a href="language.types.string.html" class="type string">string</a></span>, <span class="type"><a href="language.types.integer.html" class="type integer">integer</a></span>,
<span class="type"><a href="language.types.float.html" class="type float">float</a></span> or <span class="type"><a href="language.types.boolean.html" class="type boolean">boolean</a></span> as an input
<em><code class="parameter">value</code></em>. While most decoders will accept these values
as valid JSON, some may not, as the specification is ambiguous on this
point.
</p>
<p class="para">
To summarise, always test that your JSON decoder can handle the output you
generate from <span class="function"><strong>json_encode()</strong></span>.
</p>
</p></blockquote>
</div>
<div class="refsect1 seealso" id="refsect1-function.json-encode-seealso">
<h3 class="title">See Also</h3>
<p class="para">
<ul class="simplelist">
<li class="member"><span class="interfacename"><a href="class.jsonserializable.html" class="interfacename">JsonSerializable</a></span></li>
<li class="member"> <span class="function"><a href="function.json-decode.html" class="function" rel="rdfs-seeAlso">json_decode()</a> - Decodes a JSON string</span></li>
<li class="member"> <span class="function"><a href="function.json-last-error.html" class="function" rel="rdfs-seeAlso">json_last_error()</a> - Returns the last error occurred</span></li>
<li class="member"> <span class="function"><a href="function.serialize.html" class="function" rel="rdfs-seeAlso">serialize()</a> - Generates a storable representation of a value</span></li>
</ul>
</p>
</div>
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