# Singular and Plural keywords index
### Post version 4.27
After version 4.27 an option is available on the `Index Table -> Advanced settings` menu. After enabling the option a [new index](https://documentation.ajaxsearchpro.com/index-table/generating-the-index-table) needs to be created.
Enabling singularization and pluralization feature in Ajax Search Pro
### Pre version 4.27
{% hint style="info" %}
The tutorial below is outdated, after Ajax Search Pro 4.27 is no longer needed, please see the Post version 4.27 section above.
{% endhint %}
Use the custom code snippet below to automatically singularize and pluralize **English** keywords when using the [Index Table](https://documentation.ajaxsearchpro.com/index-table) engine. This algorightm is efficient, but of course not a 100% accurate.
{% hint style="warning" %}
After adding the code a [new index](https://documentation.ajaxsearchpro.com/index-table/generating-the-index-table) must be generated
{% endhint %}
[What is this, and where do I put this custom code?](/safe-coding-guideline.md)
```php
// ---- !!! ONLY COPY PASTE CODE BELOW THIS LINE to the functions.php in your theme directory !!! ----// ---- AJAX SEARCH PRO: BEGIN SEMI-AUTOMATIC PLURALIZATION OF ENGLISH KEYWORDS -----
class Inflect
{
static $plural = array(
'/(quiz)$/i' => "$1zes",
'/^(ox)$/i' => "$1en",
'/([m|l])ouse$/i' => "$1ice",
'/(matr|vert|ind)ix|ex$/i' => "$1ices",
'/(x|ch|ss|sh)$/i' => "$1es",
'/([^aeiouy]|qu)y$/i' => "$1ies",
'/(hive)$/i' => "$1s",
'/(?:([^f])fe|([lr])f)$/i' => "$1$2ves",
'/(shea|lea|loa|thie)f$/i' => "$1ves",
'/sis$/i' => "ses",
'/([ti])um$/i' => "$1a",
'/(tomat|potat|ech|her|vet)o$/i'=> "$1oes",
'/(bu)s$/i' => "$1ses",
'/(alias)$/i' => "$1es",
'/(octop)us$/i' => "$1i",
'/(ax|test)is$/i' => "$1es",
'/(us)$/i' => "$1es",
'/s$/i' => "s",
'/$/' => "s"
);
static $singular = array(
'/(quiz)zes$/i' => "$1",
'/(matr)ices$/i' => "$1ix",
'/(vert|ind)ices$/i' => "$1ex",
'/^(ox)en$/i' => "$1",
'/(alias)es$/i' => "$1",
'/(octop|vir)i$/i' => "$1us",
'/(cris|ax|test)es$/i' => "$1is",
'/(shoe)s$/i' => "$1",
'/(o)es$/i' => "$1",
'/(bus)es$/i' => "$1",
'/([m|l])ice$/i' => "$1ouse",
'/(x|ch|ss|sh)es$/i' => "$1",
'/(m)ovies$/i' => "$1ovie",
'/(s)eries$/i' => "$1eries",
'/([^aeiouy]|qu)ies$/i' => "$1y",
'/([lr])ves$/i' => "$1f",
'/(tive)s$/i' => "$1",
'/(hive)s$/i' => "$1",
'/(li|wi|kni)ves$/i' => "$1fe",
'/(shea|loa|lea|thie)ves$/i'=> "$1f",
'/(^analy)ses$/i' => "$1sis",
'/((a)naly|(b)a|(d)iagno|(p)arenthe|(p)rogno|(s)ynop|(t)he)ses$/i' => "$1$2sis",
'/([ti])a$/i' => "$1um",
'/(n)ews$/i' => "$1ews",
'/(h|bl)ouses$/i' => "$1ouse",
'/(corpse)s$/i' => "$1",
'/(us)es$/i' => "$1",
'/s$/i' => ""
);
static $irregular = array(
'move' => 'moves',
'foot' => 'feet',
'goose' => 'geese',
'sex' => 'sexes',
'child' => 'children',
'man' => 'men',
'tooth' => 'teeth',
'person' => 'people'
);
static $uncountable = array(
'sheep',
'fish',
'deer',
'series',
'species',
'money',
'rice',
'information',
'equipment'
);
public static function pluralize( $string )
{
// save some time in the case that singular and plural are the same
if ( in_array( strtolower( $string ), self::$uncountable ) )
return $string;
// check for irregular singular forms
foreach ( self::$irregular as $pattern => $result )
{
$pattern = '/' . $pattern . '$/i';
if ( preg_match( $pattern, $string ) )
return preg_replace( $pattern, $result, $string);
}
// check for matches using regular expressions
foreach ( self::$plural as $pattern => $result )
{
if ( preg_match( $pattern, $string ) )
return preg_replace( $pattern, $result, $string );
}
return $string;
}
public static function singularize( $string )
{
// save some time in the case that singular and plural are the same
if ( in_array( strtolower( $string ), self::$uncountable ) )
return $string;
// check for irregular plural forms
foreach ( self::$irregular as $result => $pattern )
{
$pattern = '/' . $pattern . '$/i';
if ( preg_match( $pattern, $string ) )
return preg_replace( $pattern, $result, $string);
}
// check for matches using regular expressions
foreach ( self::$singular as $pattern => $result )
{
if ( preg_match( $pattern, $string ) )
return preg_replace( $pattern, $result, $string );
}
return $string;
}
public static function pluralize_if($count, $string)
{
if ($count == 1)
return "1 $string";
else
return $count . " " . self::pluralize($string);
}
}
add_filter( 'asp_indexing_string_post_process', 'asp_index_add_singular_plural', 10, 1 );
function asp_index_add_singular_plural($s) {
$final = array();
$words = explode(' ', $s);
foreach ($words as $word) {
$singular = Inflect::singularize($word);
$plural = Inflect::pluralize($word);
$final[] = $word;
if ($singular != $word)
$final[] = $singular;
if ($plural != $word)
$final[] = $plural;
}
return implode(' ', $final);
}
// ---- AJAX SEARCH PRO: END SEMI-AUTOMATIC PLURALIZATION OF ENGLISH KEYWORDS -----
// --------------------------------------------------------------------------------
```
---
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