php function takes variable number of parameters

This article mainly introduces the use of variable number of parameters in PHP functions, which has certain reference value. Now I share it with you. Friends in need can refer to it

php supports a variable number of parameter lists in user-defined functions.

In php5.5 and earlier versions, use the func_num_args(), func_get_arg(), func_get_args() function implementation.

<?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;));

?>

<br/>

Output:

1
a
Array
(
    [0] => a
)

3
1
Array
(
    [0] => 1
    [1] => 2
    [2] => 3
)

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

Array
(
    [0] => Array
        (
            [0] => d
            [1] => e
        )

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

)

<br/>

<br/>In php5.6 and above, you can use the ... syntax.

<br/>

<?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;));

?>

<br/><br/><br/>

##Example 1: Use...$args to replace any number of arguments

<br/>

The output results are consistent with the func_num_args(), func_get_arg(), func_get_args() functions used in php5.5.

<?php

function add($a, $b){
    echo $a + $b;
}

$args = array(1, 2);

add(...$args); // 输出3

?>

<br/><br/>Example 2: Convert array to parameter list

<br/>

<?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;));

?>

<br/><br/>

Example 3: Some parameters are specified, and the number of other parameters is variable

Output:

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
        )

)

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