class test1
{
	function test1():void
	{
		$ary =[1,2,3];
		unset($ary[1]);
		print_r($ary);
/*
Array
(
    [0] => 1
    [2] => 3
)
*/
		//count を計算し、添字でアクセスした場合
		//上記の配列ではインデックスが1を削除したため
		//下記のようにfor文でcount関数を使用して実行するとエラーになります
/*
		for($i=0; $i 1
    [1] => 3
)
*/
		$data=[
			'name' => "tanaka",
			'class' => 1,
		];
		unset($data["name"]);
		print_r($data);
/*
Array
(
    [class] => 1
)
*/
	}
	function test2():void
	{
		//指定した位置から指定した数の要素を削除します。
		//複数削除や、削除と同時に値を挿入することも可能で、インデックスも自動で詰められます。
		$ary1 = ['a', 'b', 'c', 'd'];
		array_splice($ary1, 1, 2); 
		print_r($ary1);
/*
Array
(
    [0] => a
    [1] => d
)
*/
		//配列の末尾の要素を削除します。
		$ary2 = ['a', 'b', 'c'];
		array_pop($ary2); 
		print_r($ary2);
/*
Array
(
    [0] => a
    [1] => b
)
*/
		//配列の先頭の要素を削除します。
		$ary3 = ['a', 'b', 'c'];
		array_shift($ary3);
		print_r($ary3);
/*
Array
(
    [0] => b
    [1] => c
)
*/
		//渡した値と一致する値を持つ要素を削除します（キーは保持）。
		$ary4 = ['apple', 'banana', 'orange'];
		$ary4 = array_diff($ary4, ['banana']);
		print_r($ary4);
/*
Array
(
    [0] => apple
    [2] => orange
)
*/
		//条件に合う要素だけを残す（＝条件に合わない空の要素などを削除する）のに使います。
		$ary5 = [0, 1, 2, null, 3];
		$ary5 = array_filter($ary5);
		print_r($ary5);
/*
Array
(
    [1] => 1
    [2] => 2
    [4] => 3
)
*/
	}
}
echo "<pre>";
$cls1= new test1();
$cls1->test1();
$cls1->test2();
echo "</pre>";

class test1
{
	function test1():void
	{
		$ary =[1,2,3];
		unset($ary[1]);
		print_r($ary);
/*
Array
(
[0] => 1
[2] => 3
)
*/
	/Calculating count and accessing it by index
	//In the above array, index 1 has been deleted.
	//Using the count function in a for statement like the one below will result in an error.
/*
for($i=0; $i 1
[1] => 3
)
*/
	$data=[
	'name' => "tanaka",
	'class' => 1,
	];
	unset($data["name"]);
	print_r($data);
/*
Array
(
[class] => 1
)
*/
	}
	function test2():void
	{
		// Deletes the specified number of elements from the specified position.
		// Multiple deletions and simultaneous insertions are also possible, and indexes are automatically adjusted.
		$ary1 = ['a', 'b', 'c', 'd'];
		array_splice($ary1, 1, 2);
		print_r($ary1);
/*
Array
(
[0] => a
[1] => d
)
*/
		// Deletes the last element of the array.
		$ary2 = ['a', 'b', 'c'];
		array_pop($ary2);
		print_r($ary2);
/*
Array
(
[0] => a
[1] => b
)
*/
		// Remove the first element from the array.
		$ary3 = ['a', 'b', 'c'];
		array_shift($ary3);
		print_r($ary3);
/*
Array
(
[0] => b
[1] => c
)
*/
		// Remove the element whose value matches the passed value (preserving the key).
		$ary4 = ['apple', 'banana', 'orange'];
		$ary4 = array_diff($ary4, ['banana']);
		print_r($ary4);
/*
Array
(
[0] => apple
[2] => orange
)
*/
		//Used to keep only elements that meet the condition (i.e., remove empty elements that do not meet the condition).
		$ary5 = [0, 1, 2, null, 3]; 
		$ary5 = array_filter($ary5); 
		print_r($ary5);
/*
Array
( 
[1] => 1 
[2] => 2 
[4] => 3
)
*/ 
	}
}
echo "<pre>";
$cls1= new test1();
$cls1->test1();
$cls1->test2();
echo "</pre>";