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<h1 class="refname">substr_replace</h1>
<p class="verinfo">(PHP 4, PHP 5, PHP 7)</p><p class="refpurpose"><span class="refname">substr_replace</span> — <span class="dc-title">Replace text within a portion of a string</span></p>
</div>
<div class="refsect1 description" id="refsect1-function.substr-replace-description">
<h3 class="title">Description</h3>
<div class="methodsynopsis dc-description">
<span class="type"><a href="language.pseudo-types.html#language.types.mixed" class="type mixed">mixed</a></span> <span class="methodname"><strong>substr_replace</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">$string</code></span>
, <span class="methodparam"><span class="type"><a href="language.pseudo-types.html#language.types.mixed" class="type mixed">mixed</a></span> <code class="parameter">$replacement</code></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">$start</code></span>
[, <span class="methodparam"><span class="type"><a href="language.pseudo-types.html#language.types.mixed" class="type mixed">mixed</a></span> <code class="parameter">$length</code></span>
] )</div>
<p class="para rdfs-comment">
<span class="function"><strong>substr_replace()</strong></span> replaces a copy of
<code class="parameter">string</code> delimited by the
<code class="parameter">start</code> and (optionally)
<code class="parameter">length</code> parameters with the string given in
<code class="parameter">replacement</code>.
</p>
</div>
<div class="refsect1 parameters" id="refsect1-function.substr-replace-parameters">
<h3 class="title">Parameters</h3>
<p class="para">
<dl>
<dt>
<code class="parameter">string</code></dt>
<dd>
<p class="para">
The input string.
</p>
<p class="para">
An <span class="type"><a href="language.types.array.html" class="type array">array</a></span> of <span class="type"><a href="language.types.string.html" class="type string">string</a></span>s can be provided, in which
case the replacements will occur on each string in turn. In this case,
the <code class="parameter">replacement</code>, <code class="parameter">start</code>
and <code class="parameter">length</code> parameters may be provided either as
scalar values to be applied to each input string in turn, or as
<span class="type"><a href="language.types.array.html" class="type array">array</a></span>s, in which case the corresponding array element will
be used for each input string.
</p>
</dd>
<dt>
<code class="parameter">replacement</code></dt>
<dd>
<p class="para">
The replacement string.
</p>
</dd>
<dt>
<code class="parameter">start</code></dt>
<dd>
<p class="para">
If <code class="parameter">start</code> is non-negative, the replacing will
begin at the <code class="parameter">start</code>'th offset into
<code class="parameter">string</code>.
</p>
<p class="para">
If <code class="parameter">start</code> is negative, the replacing will
begin at the <code class="parameter">start</code>'th character from the
end of <code class="parameter">string</code>.
</p>
</dd>
<dt>
<code class="parameter">length</code></dt>
<dd>
<p class="para">
If given and is positive, it represents the length of the portion of
<code class="parameter">string</code> which is to be replaced. If it is
negative, it represents the number of characters from the end of
<code class="parameter">string</code> at which to stop replacing. If it
is not given, then it will default to strlen(
<code class="parameter">string</code> ); i.e. end the replacing at the
end of <code class="parameter">string</code>. Of course, if
<code class="parameter">length</code> is zero then this function will have the
effect of inserting <code class="parameter">replacement</code> into
<code class="parameter">string</code> at the given
<code class="parameter">start</code> offset.
</p>
</dd>
</dl>
</p>
</div>
<div class="refsect1 returnvalues" id="refsect1-function.substr-replace-returnvalues">
<h3 class="title">Return Values</h3>
<p class="para">
The result string is returned. If <code class="parameter">string</code> is an
array then array is returned.
</p>
</div>
<div class="refsect1 examples" id="refsect1-function.substr-replace-examples">
<h3 class="title">Examples</h3>
<p class="para">
<div class="example" id="example-6123">
<p><strong>Example #1 Simple <span class="function"><strong>substr_replace()</strong></span> examples</strong></p>
<div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br />$var </span><span style="color: #007700">= </span><span style="color: #DD0000">'ABCDEFGH:/MNRPQR/'</span><span style="color: #007700">;<br />echo </span><span style="color: #DD0000">"Original: </span><span style="color: #0000BB">$var</span><span style="color: #DD0000"><hr />\n"</span><span style="color: #007700">;<br /><br /></span><span style="color: #FF8000">/* These two examples replace all of $var with 'bob'. */<br /></span><span style="color: #007700">echo </span><span style="color: #0000BB">substr_replace</span><span style="color: #007700">(</span><span style="color: #0000BB">$var</span><span style="color: #007700">, </span><span style="color: #DD0000">'bob'</span><span style="color: #007700">, </span><span style="color: #0000BB">0</span><span style="color: #007700">) . </span><span style="color: #DD0000">"<br />\n"</span><span style="color: #007700">;<br />echo </span><span style="color: #0000BB">substr_replace</span><span style="color: #007700">(</span><span style="color: #0000BB">$var</span><span style="color: #007700">, </span><span style="color: #DD0000">'bob'</span><span style="color: #007700">, </span><span style="color: #0000BB">0</span><span style="color: #007700">, </span><span style="color: #0000BB">strlen</span><span style="color: #007700">(</span><span style="color: #0000BB">$var</span><span style="color: #007700">)) . </span><span style="color: #DD0000">"<br />\n"</span><span style="color: #007700">;<br /><br /></span><span style="color: #FF8000">/* Insert 'bob' right at the beginning of $var. */<br /></span><span style="color: #007700">echo </span><span style="color: #0000BB">substr_replace</span><span style="color: #007700">(</span><span style="color: #0000BB">$var</span><span style="color: #007700">, </span><span style="color: #DD0000">'bob'</span><span style="color: #007700">, </span><span style="color: #0000BB">0</span><span style="color: #007700">, </span><span style="color: #0000BB">0</span><span style="color: #007700">) . </span><span style="color: #DD0000">"<br />\n"</span><span style="color: #007700">;<br /><br /></span><span style="color: #FF8000">/* These next two replace 'MNRPQR' in $var with 'bob'. */<br /></span><span style="color: #007700">echo </span><span style="color: #0000BB">substr_replace</span><span style="color: #007700">(</span><span style="color: #0000BB">$var</span><span style="color: #007700">, </span><span style="color: #DD0000">'bob'</span><span style="color: #007700">, </span><span style="color: #0000BB">10</span><span style="color: #007700">, -</span><span style="color: #0000BB">1</span><span style="color: #007700">) . </span><span style="color: #DD0000">"<br />\n"</span><span style="color: #007700">;<br />echo </span><span style="color: #0000BB">substr_replace</span><span style="color: #007700">(</span><span style="color: #0000BB">$var</span><span style="color: #007700">, </span><span style="color: #DD0000">'bob'</span><span style="color: #007700">, -</span><span style="color: #0000BB">7</span><span style="color: #007700">, -</span><span style="color: #0000BB">1</span><span style="color: #007700">) . </span><span style="color: #DD0000">"<br />\n"</span><span style="color: #007700">;<br /><br /></span><span style="color: #FF8000">/* Delete 'MNRPQR' from $var. */<br /></span><span style="color: #007700">echo </span><span style="color: #0000BB">substr_replace</span><span style="color: #007700">(</span><span style="color: #0000BB">$var</span><span style="color: #007700">, </span><span style="color: #DD0000">''</span><span style="color: #007700">, </span><span style="color: #0000BB">10</span><span style="color: #007700">, -</span><span style="color: #0000BB">1</span><span style="color: #007700">) . </span><span style="color: #DD0000">"<br />\n"</span><span style="color: #007700">;<br /></span><span style="color: #0000BB">?></span>
</span>
</code></div>
</div>
</div>
</p>
<p class="para">
<div class="example" id="example-6124">
<p><strong>Example #2
Using <span class="function"><strong>substr_replace()</strong></span> to replace multiple strings at
once
</strong></p>
<div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br />$input </span><span style="color: #007700">= array(</span><span style="color: #DD0000">'A: XXX'</span><span style="color: #007700">, </span><span style="color: #DD0000">'B: XXX'</span><span style="color: #007700">, </span><span style="color: #DD0000">'C: XXX'</span><span style="color: #007700">);<br /><br /></span><span style="color: #FF8000">// A simple case: replace XXX in each string with YYY.<br /></span><span style="color: #007700">echo </span><span style="color: #0000BB">implode</span><span style="color: #007700">(</span><span style="color: #DD0000">'; '</span><span style="color: #007700">, </span><span style="color: #0000BB">substr_replace</span><span style="color: #007700">(</span><span style="color: #0000BB">$input</span><span style="color: #007700">, </span><span style="color: #DD0000">'YYY'</span><span style="color: #007700">, </span><span style="color: #0000BB">3</span><span style="color: #007700">, </span><span style="color: #0000BB">3</span><span style="color: #007700">)).</span><span style="color: #DD0000">"\n"</span><span style="color: #007700">;<br /><br /></span><span style="color: #FF8000">// A more complicated case where each replacement is different.<br /></span><span style="color: #0000BB">$replace </span><span style="color: #007700">= array(</span><span style="color: #DD0000">'AAA'</span><span style="color: #007700">, </span><span style="color: #DD0000">'BBB'</span><span style="color: #007700">, </span><span style="color: #DD0000">'CCC'</span><span style="color: #007700">);<br />echo </span><span style="color: #0000BB">implode</span><span style="color: #007700">(</span><span style="color: #DD0000">'; '</span><span style="color: #007700">, </span><span style="color: #0000BB">substr_replace</span><span style="color: #007700">(</span><span style="color: #0000BB">$input</span><span style="color: #007700">, </span><span style="color: #0000BB">$replace</span><span style="color: #007700">, </span><span style="color: #0000BB">3</span><span style="color: #007700">, </span><span style="color: #0000BB">3</span><span style="color: #007700">)).</span><span style="color: #DD0000">"\n"</span><span style="color: #007700">;<br /><br /></span><span style="color: #FF8000">// Replace a different number of characters each time.<br /></span><span style="color: #0000BB">$length </span><span style="color: #007700">= 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 />echo </span><span style="color: #0000BB">implode</span><span style="color: #007700">(</span><span style="color: #DD0000">'; '</span><span style="color: #007700">, </span><span style="color: #0000BB">substr_replace</span><span style="color: #007700">(</span><span style="color: #0000BB">$input</span><span style="color: #007700">, </span><span style="color: #0000BB">$replace</span><span style="color: #007700">, </span><span style="color: #0000BB">3</span><span style="color: #007700">, </span><span style="color: #0000BB">$length</span><span style="color: #007700">)).</span><span style="color: #DD0000">"\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>
A: YYY; B: YYY; C: YYY
A: AAA; B: BBB; C: CCC
A: AAAXX; B: BBBX; C: CCC
</pre></div>
</div>
</div>
</p>
</div>
<div class="refsect1 notes" id="refsect1-function.substr-replace-notes">
<h3 class="title">Notes</h3>
<blockquote class="note"><p><strong class="note">Note</strong>: <span class="simpara">This function is
binary-safe.</span></p></blockquote>
</div>
<div class="refsect1 seealso" id="refsect1-function.substr-replace-seealso">
<h3 class="title">See Also</h3>
<p class="para">
<ul class="simplelist">
<li class="member"><span class="function"><a href="function.str-replace.html" class="function" rel="rdfs-seeAlso">str_replace()</a> - Replace all occurrences of the search string with the replacement string</span></li>
<li class="member"><span class="function"><a href="function.substr.html" class="function" rel="rdfs-seeAlso">substr()</a> - Return part of a string</span></li>
<li class="member"><a href="language.types.string.html#language.types.string.substr" class="link">String access and modification by character</a></li>
</ul>
</p>
</div>
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