/**
* This method returns a hash map of lists of characters that are considered in the same group.
*
* @access public
* @static
* @param IArrayList\Type $xs the array list to be processed
* @param callable $subroutine the subroutine to be used
* @return IHashMap\Type a hash map of lists of characters that
* are considered in the same group
*/
public static function group(IArrayList\Type $xs, callable $subroutine) : IHashMap\Type
{
$groups = IHashMap\Type::empty_();
IString\Module::each($xs, function (IChar\Type $x, IInt32\Type $i) use($groups, $subroutine) {
$key = $subroutine($x, $i);
$item = $groups->__hasKey($key) ? $groups->item($key)->unbox() : '';
$item .= $x->unbox();
$groups->putEntry($key, IString\Type::box($item));
});
return $groups;
}
/**
* This method tests the creation of an empty list.
*/
public function testEmpty()
{
//$this->markTestIncomplete();
$p0 = IHashMap\Type::empty_();
$this->assertInstanceOf('\\Saber\\Data\\IHashMap\\Type', $p0);
$p1 = $p0->unbox();
$e1 = 0;
$this->assertInternalType('array', $p1);
$this->assertCount($e1, $p1);
}
/**
* This method returns the latter value should the former value evaluates
* to null.
*
* @access public
* @static
* @param IHashMap\Type $xs the value to be evaluated
* @param IHashMap\Type $ys the default value
* @return IHashMap\Type the result
*/
public static function nvl(IHashMap\Type $xs = null, IHashMap\Type $ys = null) : IHashMap\Type
{
return $xs ?? $ys ?? IHashMap\Type::empty_();
}
/**
* This method returns a hash map of lists of items that are considered in the same group.
*
* @access public
* @static
* @param IArrayList\Type $xs the array list to be processed
* @param callable $subroutine the subroutine to be used
* @return IHashMap\Type a hash map of lists of items that
* are considered in the same group
*/
public static function group(IArrayList\Type $xs, callable $subroutine) : IHashMap\Type
{
$groups = IHashMap\Type::empty_();
$xi = IArrayList\Module::iterator($xs);
foreach ($xi as $i => $x) {
$key = $subroutine($x, $i);
$item = $groups->__hasKey($key) ? $groups->item($key)->unbox() : array();
$item[] = $x;
$groups->putEntry($key, IArrayList\Type::box($item));
}
return $groups;
}
