PHP関数の変数パラメータ数とは何ですか

<?php
function myfunc(){

    // 获取参数数量
    echo func_num_args().PHP_EOL;    // 获取第一个参数的值：
    print_r(func_get_arg(0));    echo PHP_EOL;    // 获取所有参数的值
    print_r(func_get_args());    echo PHP_EOL;

}

myfunc(&#39;a&#39;);
myfunc(1, 2, 3);
myfunc(array(&#39;d&#39;,&#39;e&#39;), array(&#39;f&#39;));
?>

1aArray(
    [0] => a
)31Array(
    [0] => 1
    [1] => 2
    [2] => 3)2Array(
    [0] => d
    [1] => e
)Array(
    [0] => Array
        (
            [0] => d
            [1] => e
        )

    [1] => Array
        (
            [0] => f
        )

)

<?php
function myfunc(...$args){

    // 获取参数数量
    echo count($args).PHP_EOL;    // 获取第一个参数的值：
    print_r($args[0]);    echo PHP_EOL;    // 获取所有参数的值
    print_r($args);    echo PHP_EOL;

}

myfunc(&#39;a&#39;);
myfunc(1, 2, 3);
myfunc(array(&#39;d&#39;,&#39;e&#39;), array(&#39;f&#39;));
?>

<?php
function add($a, $b){
    echo $a + $b;
}
$args = array(1, 2);

add(...$args); // 输出3
?>

<?php
function display($name, $tag, ...$args){
    echo &#39;name:&#39;.$name.PHP_EOL;    
    echo &#39;tag:&#39;.$tag.PHP_EOL;    
    echo &#39;args:&#39;.PHP_EOL;
    print_r($args);    
    echo PHP_EOL;
}

display(&#39;fdipzone&#39;, &#39;programmer&#39;);
display(&#39;terry&#39;, &#39;designer&#39;, 1, 2);
display(&#39;aoao&#39;, &#39;tester&#39;, array(&#39;a&#39;,&#39;b&#39;), array(&#39;c&#39;), array(&#39;d&#39;));
?>

name:fdipzone
tag:programmer
args:Array(
)

name:terry
tag:designer
args:Array(
    [0] => 1
    [1] => 2)

name:aoao
tag:tester
args:Array(
    [0] => Array
        (
            [0] => a
            [1] => b
        )

    [1] => Array
        (
            [0] => c
        )

    [2] => Array
        (
            [0] => d
        )

)