empty(): Improve examples (#4394)

- Remove deprecated example
- Add multidimensional arrays examples

---------

Co-authored-by: Luffy <52o@qq52o.cn>
Co-authored-by: Gina Peter Banyard <girgias@php.net>

Author: 3 people

reference/var/functions/empty.xml

@@ -29,6 +29,7 @@
        No warning is generated if the variable does not exist.
        That means <function>empty</function> is essentially the
        concise equivalent to <command>!isset($var) || $var == false</command>.
+       This also applies to nested structures, such as a multidimensional array or chained properties.
       </para>
      </listitem>
     </varlistentry>
@@ -79,7 +80,6 @@ $expected_array_got_string = 'somestring';
 var_dump(empty($expected_array_got_string['some_key']));
 var_dump(empty($expected_array_got_string[0]));
 var_dump(empty($expected_array_got_string['0']));
-var_dump(empty($expected_array_got_string[0.5]));
 var_dump(empty($expected_array_got_string['0.5']));
 var_dump(empty($expected_array_got_string['0 Mostel']));
 ?>
@@ -91,9 +91,40 @@ var_dump(empty($expected_array_got_string['0 Mostel']));
 bool(true)
 bool(false)
 bool(false)
-bool(false)
 bool(true)
 bool(true)
+]]>
+   </screen>
+  </example>
+  <example>
+   <title><function>empty</function> on multidimensional arrays</title>
+   <programlisting role="php">
+<![CDATA[
+<?php
+$multidimensional = [
+    'some' => [
+        'deep' => [
+            'nested' => 'value'
+        ]
+    ]
+];
+
+if (!empty($multidimensional['some']['some']['nested'])) {
+    $someVariable = $multidimensional['some']['deep']['nested'];
+}
+
+var_dump(empty($multidimensional['some-undefined-key']));
+var_dump(empty($multidimensional['some']['deep']['unknown']));
+var_dump(empty($multidimensional['some']['deep']['nested']));
+?>
+]]>
+   </programlisting>
+   &example.outputs;
+   <screen>
+<![CDATA[
+bool(true)
+bool(true)
+bool(false)
 ]]>
    </screen>
   </example>