php-doc-en/reference/var/functions/is-numeric.xml

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<!-- $Revision$ -->
<refentry xml:id="function.is-numeric" xmlns="http://docbook.org/ns/docbook">
 <refnamediv>
  <refname>is_numeric</refname>
  <refpurpose>
   Finds whether a variable is a number or a numeric string
  </refpurpose>
 </refnamediv>

 <refsect1 role="description">
  &reftitle.description;
  <methodsynopsis>
   <type>bool</type><methodname>is_numeric</methodname>
   <methodparam><type>mixed</type><parameter>var</parameter></methodparam>
  </methodsynopsis>
  <para>
   Finds whether the given variable is numeric. Numeric strings consist of optional
   whitespace, optional
   sign, any number of digits, optional decimal part and optional exponential part.
   Thus <literal>+0123.45e6</literal> is a valid numeric value. Hexadecimal (e.g.
   <literal>0xf4c3b00c</literal>) and binary (e.g. <literal>0b10100111001</literal>)
   notation is not allowed.
  </para>
 </refsect1>

 <refsect1 role="parameters">
  &reftitle.parameters;
  <para>
   <variablelist>
    <varlistentry>
     <term><parameter>var</parameter></term>
     <listitem>
      <para>
       The variable being evaluated.
      </para>
     </listitem>
    </varlistentry>
   </variablelist>
  </para>
 </refsect1>

 <refsect1 role="returnvalues">
  &reftitle.returnvalues;
  <para>
   Returns &true; if <parameter>var</parameter> is a number or a numeric
   string, &false; otherwise.
  </para>
 </refsect1>

 <refsect1 role="examples">
  &reftitle.examples;
  <para>
   <example>
    <title><function>is_numeric</function> examples</title>
    <programlisting role="php">
<![CDATA[
<?php
$tests = array(
    "42",
    1337,
    0x539,
    02471,
    0b10100111001,
    1337e0,
    "0x539",
    "02471",
    "0b10100111001",
    "1337e0",
    "not numeric",
    array(),
    9.1,
    null
);

foreach ($tests as $element) {
    if (is_numeric($element)) {
        echo var_export($element, true) . " is numeric", PHP_EOL;
    } else {
        echo var_export($element, true) . " is NOT numeric", PHP_EOL;
    }
}
?>
]]>
    </programlisting>
    &example.outputs;
    <screen>
<![CDATA[
'42' is numeric
1337 is numeric
1337 is numeric
1337 is numeric
1337 is numeric
1337.0 is numeric
'0x539' is NOT numeric
'02471' is numeric
'0b10100111001' is NOT numeric
'1337e0' is numeric
'not numeric' is NOT numeric
array (
) is NOT numeric
9.1 is numeric
NULL is NOT numeric
]]>
    </screen>
   </example>
  </para>
 </refsect1>

 <refsect1 role="changelog"><!-- {{{ -->
  &reftitle.changelog;
  <para>
   <informaltable>
    <tgroup cols="2">
     <thead>
      <row>
       <entry>&Version;</entry>
       <entry>&Description;</entry>
      </row>
     </thead>
     <tbody>
      <row>
       <entry>7.0.0</entry>
       <entry>
        Strings in hexadecimal (e.g. <literal>0xf4c3b00c</literal>) notation are
        no longer regarded as numeric strings, i.e.
        <function>is_numeric</function> returns &false; now.
       </entry>
      </row>
     </tbody>
    </tgroup>
   </informaltable>
  </para>
 </refsect1><!-- }}} -->

 <refsect1 role="seealso">
  &reftitle.seealso;
  <para>
   <simplelist>
    <member><function>ctype_digit</function></member>
    <member><function>is_bool</function></member>
    <member><function>is_null</function></member>
    <member><function>is_float</function></member>
    <member><function>is_int</function></member>
    <member><function>is_string</function></member>
    <member><function>is_object</function></member>
    <member><function>is_array</function></member>
   </simplelist>
  </para>
 </refsect1>

</refentry>

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