PHP7新特性

Generator syntax 新方法实现迭代

function gen_one_to_three() {
    for ($i = 1; $i <= 3; $i++) {
        // Note that $i is preserved between yields.
        yield $i;
    }
}

$generator = gen_one_to_three();
foreach ($generator as $value) {
    echo "$value\n";
}

Yielding values with keys

$input = <<<'EOF'
1;PHP;Likes dollar signs
2;Python;Likes whitespace
3;Ruby;Likes blocks
EOF;

function input_parser($input) {
    foreach (explode("\n", $input) as $line) {
        $fields = explode(';', $line);
        $id = array_shift($fields);

        yield $id => $fields;
    }
}

foreach (input_parser($input) as $id => $fields) {
    echo "$id:\n";
    echo "    $fields[0]\n";
    echo "    $fields[1]\n";
}

Constants

const ANIMALS = array('dog', 'cat', 'bird');
echo ANIMALS[1]; // outputs "cat"

// Works as of PHP 7
define('ANIMALS', [
    'dog',
    'cat',
    'bird'
]);
echo ANIMALS[1]; // outputs "cat"

返回值类型声明

function hello() : array
{
    return [];
}

NULL 合并运算符 (免去三元表达式的繁琐)

$username = $_GET['username'] ?? null;
// 等价于
$username = isset($_GET['username']) ? $_GET['username'] : null;
//注意，下面的写法是错误的， $username 的值变成true/false 了。
$username = isset($_GET['username']) ?? null;

通过 define() 定义常量数组

define('ANIMALS', [
    'dog',
    'cat',
    'bird'
]);

整除

var_dump(intdiv(10, 3));  => 3

PHP7.1 特性

https://secure.php.net/manual/en/migration71.new-features.php

Nullable types

function testReturn(): ?string
{
    return 'elePHPant';
}

Void functions

function swap(&$left, &$right): void
{
    if ($left === $right) {
        return;
    }

    $tmp = $left;
    $left = $right;
    $right = $tmp;
}