public function testDifference()
{
// Using the default comparator.
$array0 = CArray::fromElements("a", "b", "c", "d", "e", "f");
$array1 = CArray::fromElements("g", "b", "h", "d", "i", "f");
$array = CArray::difference($array0, $array1);
$this->assertTrue(CArray::equals($array, CArray::fromElements("a", "c", "e")));
// Using a custom comparator.
$array0 = CArray::fromElements("a", "b", "c", "d", "e", "f");
$array1 = CArray::fromElements("G", "B", "H", "D", "I", "F");
$comparator = function ($string0, $string1) {
return CString::toLowerCase($string0) === CString::toLowerCase($string1);
};
$array = CArray::difference($array0, $array1, $comparator);
$this->assertTrue(CArray::equals($array, CArray::fromElements("a", "c", "e")));
}
/**
* From an array, removes only those elements that are present in another array and returns the new array.
*
* In the operation, *this* array is the minuend and the parameter array is the subtrahend.
*
* None of the source arrays is modified by this method.
*
* You can use your own comparator for the comparison of the elements in the arrays, but the default comparator has
* got you covered when comparing scalar values, such as `string`, `int`, `float`, and `bool`. And the default
* comparator is smart enough to know how to compare objects of those classes that conform to the IEquality or
* IEqualityAndOrder interface (static or not), including CUStringObject, CArrayObject, CMapObject, CTime etc. See
* the [CComparator](CComparator.html) class for more on this.
*
* @param array $subtrahendArray The subtrahend array.
* @param callable $comparator **OPTIONAL. Default is** `CComparator::EQUALITY`. The function or method to be
* used for the comparison of any two elements. If this parameter is provided, the comparator should take two
* parameters, with the first parameter being an element from the minuend array and the second parameter being an
* element from the subtrahend array, and return `true` if the two elements are equal and `false` otherwise.
*
* @return CArrayObject The difference array after subtracting the subtrahend array from the minuend array.
*
* @link CComparator.html CComparator
*/
public function difference($subtrahendArray, $comparator = CComparator::EQUALITY)
{
return self::fromSplArray(CArray::difference($this->m_splArray, $subtrahendArray, $comparator));
}
