reference/math/functions/pow.xml
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<refsect1 role="description">
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&reftitle.description;
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<methodsynopsis>
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<type>number</type><methodname>pow</methodname>
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<methodparam><type>number</type><parameter>base</parameter></methodparam>
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<methodparam><type>number</type><parameter>exp</parameter></methodparam>
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</methodsynopsis>
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<type class="union"><type>int</type><type>float</type><type>object</type></type><methodname>pow</methodname>
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<methodparam><type>mixed</type><parameter>num</parameter></methodparam>
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<methodparam><type>mixed</type><parameter>exponent</parameter></methodparam>
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</methodsynopsis>
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<para>
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Returns <parameter>base</parameter> raised to the power of
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<parameter>exp</parameter>.
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Returns <parameter>num</parameter> raised to the power of
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<parameter>exponent</parameter>.
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</para>
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<note>
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<para>
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It is possible to use the <link linkend="language.operators.arithmetic">**</link> operator instead.
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</para>
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</note>
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</refsect1>
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<refsect1 role="parameters">
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&reftitle.parameters;
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<para>
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<variablelist>
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<varlistentry>
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<term><parameter>base</parameter></term>
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<term><parameter>num</parameter></term>
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<listitem>
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<para>
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The base to use
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><parameter>exp</parameter></term>
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<term><parameter>exponent</parameter></term>
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<listitem>
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<para>
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The exponent
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<refsect1 role="returnvalues">
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&reftitle.returnvalues;
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<para>
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<parameter>base</parameter> raised to the power of <parameter>exp</parameter>.
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<parameter>num</parameter> raised to the power of <parameter>exponent</parameter>.
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If both arguments are non-negative integers and the result can be represented
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as an integer, the result will be returned with <type>integer</type> type,
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as an integer, the result will be returned with <type>int</type> type,
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otherwise it will be returned as a <type>float</type>.
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</para>
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<para>
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PHP-Extensions may override the behaviour of this operation and make it return an object.
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</para>
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</refsect1>
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<refsect1 role="changelog">
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&reftitle.changelog;
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<para>
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<informaltable>
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<tgroup cols="2">
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<thead>
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<row>
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<entry>&Version;</entry>
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<entry>&Description;</entry>
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</row>
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</thead>
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<tbody>
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<row>
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<entry>4.2.0</entry>
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<entry>
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No warning is emitted on errors, even if the value can't be computed.
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</entry>
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</row>
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<row>
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<entry>4.0.6</entry>
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<entry>
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The function will now return <type>integer</type> results if possible,
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before this it always returned a <type>float</type> result. For older
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versions, you may receive a bogus result for complex numbers.
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</entry>
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</row>
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</tbody>
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</tgroup>
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</informaltable>
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</para>
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<informaltable>
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<tgroup cols="2">
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<thead>
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<row>
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<entry>&Version;</entry>
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<entry>&Description;</entry>
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</row>
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</thead>
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<tbody>
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<row>
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<entry>8.4.0</entry>
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<entry>
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Raising <literal>0</literal> to a negative
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<parameter>exponent</parameter> is now deprecated.
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</entry>
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</row>
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</tbody>
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</tgroup>
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</informaltable>
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</refsect1>
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<refsect1 role="examples">
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&reftitle.examples;
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<para>
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<?php
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var_dump(pow(2, 8)); // int(256)
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echo pow(-1, 20); // 1
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echo pow(0, 0); // 1
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echo pow(-1, 20), PHP_EOL; // 1
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echo pow(0, 0), PHP_EOL; // 1
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echo pow(10, -1), PHP_EOL; // 0.1
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echo pow(-1, 5.5); // PHP >4.0.6 NAN
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echo pow(-1, 5.5); // PHP <=4.0.6 1.#IND
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echo pow(-1, 5.5), PHP_EOL; // NAN
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?>
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]]>
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</programlisting>
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</example>
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</para>
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<para>
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<example>
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<title>Examples of <function>pow</function> With GMP Extension Object</title>
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<programlisting role="php" annotations="non-interactive">
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<![CDATA[
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<?php
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var_dump(pow(new GMP("3"), new GMP("2"))); // object(GMP)
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?>
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]]>
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</programlisting>
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<note>
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<para>
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This function will convert all input to a number, even non-scalar values,
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which could lead to <literal>weird</literal> results.
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which could lead to <emphasis>weird</emphasis> results.
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</para>
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</note>
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</refsect1>
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&reftitle.seealso;
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<para>
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<simplelist>
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<member>
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Exponentiation operator
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<link linkend="language.operators.arithmetic"><literal>**</literal></link>
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</member>
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<member><function>fpow</function></member>
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<member><function>exp</function></member>
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<member><function>sqrt</function></member>
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<member><function>bcpow</function></member>
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</para>
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</refsect1>
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</refentry>
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<!-- Keep this comment at the end of the file
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Local variables:
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mode: sgml
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Translation status