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>value</parameter></methodparam>
  </methodsynopsis>
  <para>
   Determines if the given variable is a number or a
   <link linkend="language.types.numeric-strings">numeric string</link>.
  </para>
 </refsect1>

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

 <refsect1 role="returnvalues">
  &reftitle.returnvalues;
  <para>
   Returns &true; if <parameter>value</parameter> is a number or a
   <link linkend="language.types.numeric-strings">numeric string</link>,
   &false; otherwise.
  </para>
 </refsect1>

 <refsect1 role="changelog">
  &reftitle.changelog;
  <informaltable>
   <tgroup cols="2">
    <thead>
     <row>
      <entry>&Version;</entry>
      <entry>&Description;</entry>
     </row>
    </thead>
    <tbody>
     <row>
      <entry>8.0.0</entry>
      <entry>
       Numeric strings ending with whitespace (<literal>"42 "</literal>) will now
       return &true;. Previously, &false; was returned instead.
      </entry>
     </row>
    </tbody>
   </tgroup>
  </informaltable>
 </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
'' is NOT numeric
]]>
    </screen>
   </example>
  </para>

  <para>
   <example>
    <title><function>is_numeric</function> with whitespace</title>
    <programlisting role="php">
     <![CDATA[
<?php
$tests = [
    " 42",
    "42 ",
    "\u{A0}9001", // non-breaking space
    "9001\u{A0}", // non-breaking space
];

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.8;
    <screen>
     <![CDATA[
' 42' is numeric
'42 ' is numeric
' 9001' is NOT numeric
'9001 ' is NOT numeric
]]>
    </screen>
    &example.outputs.7;
    <screen>
     <![CDATA[
' 42' is numeric
'42 ' is NOT numeric
' 9001' is NOT numeric
'9001 ' is NOT numeric
]]>
    </screen>
   </example>
  </para>
 </refsect1>

 <refsect1 role="seealso">
  &reftitle.seealso;
  <para>
   <simplelist>
    <member><link linkend="language.types.numeric-strings">Numeric strings</link></member>
    <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>
    <member><function>filter_var</function></member>
   </simplelist>
  </para>
 </refsect1>

</refentry>
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