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<?xml version="1.0" encoding="utf-8"?>
<!-- $Revision$ -->
<!-- splitted from ./en/functions/strings.xml, last change in rev 1.2 -->
<refentry xml:id="function.trim" xmlns="http://docbook.org/ns/docbook">
<refnamediv>
<refname>trim</refname>
<refpurpose>Strip whitespace (or other characters) from the beginning and end of a string</refpurpose>
</refnamediv>
<refsect1 role="description">
&reftitle.description;
<methodsynopsis>
<type>string</type><methodname>trim</methodname>
<methodparam><type>string</type><parameter>string</parameter></methodparam>
<methodparam choice="opt"><type>string</type><parameter>characters</parameter><initializer>" \n\r\t\v\x00"</initializer></methodparam>
</methodsynopsis>
<simpara>
This function returns a string with whitespace stripped from the
beginning and end of <parameter>string</parameter>.
Without the second parameter,
<function>trim</function> will strip these characters:
</simpara>
&strings.stripped.characters;
</refsect1>
<refsect1 role="parameters">
&reftitle.parameters;
<variablelist>
<varlistentry>
<term><parameter>string</parameter></term>
<listitem>
<para>
The <type>string</type> that will be trimmed.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>characters</parameter></term>
<listitem>
&strings.parameter.characters.optional;
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1 role="returnvalues">
&reftitle.returnvalues;
<simpara>
The trimmed string.
</simpara>
</refsect1>
<refsect1 role="examples">
&reftitle.examples;
<para>
<example>
<title>Usage example of <function>trim</function></title>
<programlisting role="php">
<![CDATA[
<?php
$text = "\t\tThese are a few words :) ... ";
$binary = "\x09Example string\x0A";
$hello = "Hello World";
var_dump($text, $binary, $hello);
print "\n";
$trimmed = trim($text);
var_dump($trimmed);
$trimmed = trim($text, " \t.");
var_dump($trimmed);
$trimmed = trim($hello, "Hdle");
var_dump($trimmed);
$trimmed = trim($hello, 'HdWr');
var_dump($trimmed);
// trim the ASCII control characters at the beginning and end of $binary
// (from 0 to 31 inclusive)
$clean = trim($binary, "\x00..\x1F");
var_dump($clean);
?>
]]>
</programlisting>
&example.outputs;
<screen>
<![CDATA[
string(32) " These are a few words :) ... "
string(16) " Example string
"
string(11) "Hello World"
string(28) "These are a few words :) ..."
string(24) "These are a few words :)"
string(5) "o Wor"
string(9) "ello Worl"
string(14) "Example string"
]]>
</screen>
</example>
</para>
<para>
<example>
<title>Trimming array values with <function>trim</function></title>
<programlisting role="php">
<![CDATA[
<?php
function trim_value(&$value)
{
$value = trim($value);
}
$fruit = array('apple','banana ', ' cranberry ');
var_dump($fruit);
array_walk($fruit, 'trim_value');
var_dump($fruit);
?>
]]>
</programlisting>
&example.outputs;
<screen>
<![CDATA[
array(3) {
[0]=>
string(5) "apple"
[1]=>
string(7) "banana "
[2]=>
string(11) " cranberry "
}
array(3) {
[0]=>
string(5) "apple"
[1]=>
string(6) "banana"
[2]=>
string(9) "cranberry"
}
]]>
</screen>
</example>
</para>
</refsect1>
<refsect1 role="notes">
&reftitle.notes;
<note>
<title>Possible gotcha: removing middle characters</title>
<para>
Because <function>trim</function> trims characters from the beginning and end of
a <type>string</type>, it may be confusing when characters are (or are not) removed from
the middle. <literal>trim('abc', 'bad')</literal> removes both 'a' and 'b' because it
trims 'a' thus moving 'b' to the beginning to also be trimmed. So, this is why it "works"
whereas <literal>trim('abc', 'b')</literal> seemingly does not.
</para>
</note>
</refsect1>
<refsect1 role="seealso">
&reftitle.seealso;
<simplelist>
<member><function>ltrim</function></member>
<member><function>rtrim</function></member>
<member><function>str_replace</function></member>
</simplelist>
</refsect1>
</refentry>
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