php - 数组声明中的 PHP 传播语法

Question

PHP 支持可变参数函数的扩展语法。

在 JavaScript 中，您可以使用扩展语法来执行此操作：

var a = [1, 2];
var b = [...a, 3, 4];
console.log(b); // [1, 2, 3, 4]

但是，尝试在 PHP 中执行此操作：

$a = [1, 2];
$b = [...$a, 3, 4];
var_dump($b);die;

导致此错误：

解析错误：语法错误，意外的 '...' (T_ELLIPSIS)，期待 ']'

PHP中不允许以这种方式使用传播语法吗？如果是这样，是否有一种同样优雅的方式来达到同样的效果？

Answer 1

The spread operator in the arrays RFC has been implemented in PHP 7.4:

$ary = [3, 4, 5];
return [1, 2, ...$ary]; // same as [1, 2, 3, 4, 5]

Caveat: The unpacked array/Traversable can only have integer keys. For string keys array_merge() is still required.

Answer 2

Answer 3

In PHP 7.4 you can now use Spread Operators in array expressions.

$parts = ['apple', 'pear'];
$fruits = ['banana', 'orange', ...$parts, 'watermelon'];
// ['banana', 'orange', 'apple', 'pear', 'watermelon'];

Answer 4

Below PHP 7.4

$mainArray = ['element1', 'element2'];
$finalArray = array_merge($mainArray, ['element3']);
print_r($finalArray);
// Final array would be ['element1', 'element2', 'element3'];

In or Above PHP 7.4

$mainArray = ['element1', 'element2'];
$finalArray = [...$mainArray, 'element3'];
print_r($finalArray);
// Final array would be ['element1', 'element2', 'element3'];