即将推出的 PHP8 的展开运算符和它之前存在的紧凑函数有什么区别？

Question

即将推出的 PHP8 的展开运算符和它之前存在的 compact() 函数有什么区别？

$data = new CustomerData(...$input);

Answer 1

紧凑运算符和展开运算符之间的区别

紧凑PHP函数:

compact — Create array containing variables and their values

<?php
$city  = "San Francisco";
$state = "CA";
$event = "SIGGRAPH";

$location_vars = array("city", "state");

$result = compact("event", $location_vars);
print_r($result);
?>

哪个输出：

Array
(
    [event] => SIGGRAPH
    [city] => San Francisco
    [state] => CA
)

数组展开：

while array spreading merge two or more array without adding a key to his value (associative array):

$arr1 = [1, 2, 3];
$arr2 = [...$arr1]; //[1, 2, 3]
$arr3 = [0, ...$arr1]; //[0, 1, 2, 3]
$arr4 = array(...$arr1, ...$arr2, 111); //[1, 2, 3, 1, 2, 3, 111]
$arr5 = [...$arr1, ...$arr1]; //[1, 2, 3, 1, 2, 3]

数组展开也可用于填充方法调用的参数，假设您的 class:

具有此构造函数

class CustomerData
{
    public function __construct(
        public string $name,
        public string $email,
        public int $age,
    ) {}
}

并使用数组展开创建CustomerData对象：

$input = [
    'age' => 25,
    'name' => 'Brent',
    'email' => 'brent@stitcher.io',
];

$data = new CustomerData(...$input);

与以下行为相同：

$input = [
    'age' => 25,
    'name' => 'Brent',
    'email' => 'brent@stitcher.io',
];

$data = new CustomerData($input['age'], $input['name'], $input['email']);

PHP has already supported argument unpacking (AKA spread operator) since 5.6. This RFC proposes to bring this feature to array expression.

自 PHP 7.4.

以来还实现了数组表达式中的展开运算符

来源：

PHP: compact - Manual

PHP: Spread Operator in Array Expression

即将到来 PHP 8: 命名参数

发件人：PHP 8: named arguments

Named arguments allow passing arguments to a function based on the parameter name, rather than the parameter position. This makes the meaning of the argument self-documenting, makes the arguments order-independent, and allows skipping default values arbitrarily

class CustomerData
{
    public function __construct(
        public string $name,
        public string $email,
        public int $age,
    ) {}
}

$data = new CustomerData(
    name: $input['name'],
    email: $input['email'],
    age: $input['age'],
);

即将推出的 PHP8 的展开运算符和它之前存在的紧凑函数有什么区别？

What's the difference between upcoming PHP8's spread operator and it's pre-existing compact function?

php

php-8

紧凑运算符和展开运算符之间的区别

即将到来 PHP 8: 命名参数