Boundary conditions and special cases for PHP array intersection and union

PHP The processing method of array intersection and union is as follows: Intersection: Find elements that exist in two arrays at the same time. The boundary condition is an empty array or contains duplicate elements. The processing method only includes one copy; Union: Find two All unique elements contained in an array, with boundary conditions being an empty array or containing different data types, are handled in a manner that results in non-integer keys.

Boundary conditions and special cases of PHP array intersection and union

Intersection

• Objective: Find the elements that exist in two arrays at the same time.

• Boundary conditions:

  • If any array is empty, the intersection is empty.
  • There are duplicate elements in the array, and only one copy is included in the intersection.

• Special case:

  • The array contains different data types, and the intersection is empty.

// 获取两个数组的交集
$arr1 = [1, 2, 3, 4, 5];
$arr2 = [3, 4, 5, 6, 7];
$intersection = array_intersect($arr1, $arr2);

// 输出交集元素
echo implode(', ', $intersection); // 输出：3, 4, 5

Union

• ##Goal: Find all unique values ​​contained in the two arrays element.

• Boundary conditions:

  If any array is empty, the union is another array.

• Special case:

  The array contains different data types and the keys of the union will be non-integer.

// 获取两个数组的并集
$arr1 = [1, 2, 3, 4, 5];
$arr2 = [3, 4, 5, 6, 7];
$union = array_merge($arr1, $arr2);

// 输出并集元素
echo implode(', ', $union); // 输出：1, 2, 3, 4, 5, 6, 7

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