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<?php # http://scribu.net/blog/defaultdict-in-php.html class Defaultdict implements ArrayAccess { private $container = array(); private $default; public function __construct( $default ) { $this->default = $default; } public function offsetSet( $offset, $value ) { if ( is_null($offset) ) { trigger_error( sprintf( "Trying to use %s as a list.", __CLASS__ ), E_USER_WARNING ); return; } $this->container[$offset] = $value; } public function offsetExists( $offset ) { return true; } public function offsetUnset( $offset ) { unset( $this->container[$offset] ); } public function &offsetGet( $offset ) { if ( !isset( $this->container[$offset] ) ) { if ( is_callable($this->default) ) $value = call_user_func( $this->default, $offset ); else $value = $this->default; $this->container[$offset] = $value; } return $this->container[$offset]; } } $counts = new Defaultdict(1); $counts['English']++; print_r(array_keys($counts));

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