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

<?xml version="1.0" encoding="utf-8"?>
<!-- $Revision$ -->
<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
   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,
    "not numeric",
    array(),
    9.1
);

foreach ($tests as $element) {
    if (is_numeric($element)) {
        echo "'{$element}' is numeric", PHP_EOL;
    } else {
        echo "'{$element}' 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' is numeric
'not numeric' is NOT numeric
'Array' is NOT numeric
'9.1' is 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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