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    新的特性

    新增 Generators

    Support for generators has been added via the yield keyword. Generators provide an easy way to implement simple iterators without the overhead or complexity of implementing a class that implements the Iterator interface.

    A simple example that reimplements the range() function as a generator (at least for positive step values):

    <?php
    function xrange($start, $limit, $step = 1) {
        for (    $i = $start; $i <= $limit; $i += $step) {
            yield     $i;
        }
    }

    echo     'Single digit odd numbers: ';

    /* 注意保存在内存中的数组绝不会被创建或返回 */ 
    foreach (xrange(1, 9, 2) as $number) {
        echo     "$number ";
    }
    ?>

    以上例程会输出：

    Single digit odd numbers: 1 3 5 7 9

    新增 finally 关键字

    try-catch blocks now support a finally block for code that should be run regardless of whether an exception has been thrown or not.

    foreach 现在支持 list()

    foreach 控制结构现在支持通过 list() 构造将嵌套数组分离到单独的变量。例如：

    <?php
    $array     = [
        [    1, 2],
        [    3, 4],
    ];

    foreach (    $array as list($a, $b)) {
        echo     "A: $a; B: $b\n";
    }
    ?>

    以上例程会输出：

    A: 1; B: 2
A: 3; B: 4

    关于 foreach 更深入的文档可参考相关手册页面。

    empty() 支持任意表达式

    empty() 现在支持传入一个任意表达式，而不仅是一个变量。例如：

    <?php
    function always_false() {
        return     false;
    }

    if (empty(    always_false())) {
        echo     'This will be printed.';
    }

    if (empty(    true)) {
        echo     'This will not be printed.';
    }
    ?>

    以上例程会输出：

    This will be printed.

    array and string literal dereferencing

    Array and string literals can now be dereferenced directly to access individual elements and characters:

    <?php
    echo 'Array dereferencing: ';
    echo [    1, 2, 3][0];
    echo     "\n";

    echo     'String dereferencing: ';
    echo     'PHP'[0];
    echo     "\n";
    ?>

    以上例程会输出：

    Array dereferencing: 1
String dereferencing: P

    新的密码哈希 API

    A 新的密码哈希 API that makes it easier to securely hash and manage passwords using the same underlying library as crypt() in PHP has been added. See the documentation for password_hash() for more detail.

    Apache 2.4 handler supported on Windows

    The Apache 2.4 handler SAPI is now supported on Windows.

    改进 GD

    对 GD 扩展做了多方面的改进，包括：

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    User Contributed Notes 3 notes

    up
    13
    PHP Guy
    11 years ago
    Great work.  Thank you for allowing Lists to return on foreach.
    up
    1
    Anonymous
    9 years ago
    Yield is awesome... it's starts to look like a real language now ;-)

    class myList {
        public $list;
        public function __construct($list) {
            $this->list = $list;
        }

        public function select(...$keys) {
            $keys_array = array_fill_keys($keys, null);
            $items = $this->list;
            foreach($items as $item) {
                yield array_merge($keys_array, array_intersect_key($item, $keys_array));
            }
        }
    }
    up
    0
    wallacemaxters at gmail dot com
    8 years ago
    After PHP 5.5, foreach with reference in arbitrary array does not generate an error:

        foreach ([1, 2, 3, 4] as $key => &$value) {
            $value = $value . ' R$';
        }

    before 5.4, will generate  "Cannot create references to elements of a temporary array expression"
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