New features in PHP7

Scalar type declaration

• Forced mode (default) strict mode

• Strict mode

declare(strict_types=1);

• #int

##float
bool
string
interfaces
array
callable

<?php
// 强制模式
function sum(int ...$ints)
{
   return array_sum($ints);
}
print(sum(2, '3', 4.1));
?>

9

The example summary will Parameter 4.1 is converted to an integer 4 and then added.

<?php
// 严格模式
declare(strict_types=1);

function sum(int ...$ints)
{
   return array_sum($ints);
}

print(sum(2, '3', 4.1));
?>

PHP Fatal error:  Uncaught TypeError: Argument 2 passed to sum() must be of the type integer, string given, called in……

Return type declarationPHP 7 adds support for return type declaration, which specifies the function return The type of value.

The return types that can be declared are:

#int

• ##float

• bool

• string

• interfaces

• array

• callable
Return type declaration example:

In the example, the return result is required to be an integer:

<?php
declare(strict_types=1);
function returnIntValue(int $value): int
{
   return $value;
}
print(returnIntValue(5));
?>

The above program execution output result is:

5

Return type declaration error example:

<?php
declare(strict_types=1);

function returnIntValue(int $value): int
{
   return $value + 1.0;
}

print(returnIntValue(5));
?>

Since the above program adopts strict mode, the return value must be int, but the calculation result is float, so an error will be reported. The execution output result is:

Fatal error: Uncaught TypeError: Return value of returnIntValue() must be of the type integer, float returned...

②PHP NULL merging operator

PHP 7’s newly added NULL merging operator (??) is a shortcut for performing ternary operations detected by isset().

The NULL coalescing operator will determine whether the variable exists and the value is not NULL. If so, it will return its own value, otherwise it will return its second operand.

We used to write the ternary operator like this:

$site = isset($_GET['site']) ? $_GET['site'] : 'PHP中文网';

Now we can write it directly like this:

$site = $_GET['site'] ?? 'PHP中文网';

Example

<?php
// 获取 $_GET['site'] 的值，如果不存在返回 'PHP中文网'
$site = $_GET['site'] ?? 'PHP中文网';

print($site);
print(PHP_EOL); // PHP_EOL 为换行符

// 以上代码等价于
$site = isset($_GET['site']) ? $_GET['site'] : 'PHP中文网';

print($site);
print(PHP_EOL);
// ?? 链
$site = $_GET['site'] ?? $_POST['site'] ?? 'PHP中文网';

print($site);
?>

The execution output of the above program is:

PHP中文网
PHP中文网
PHP中文网

③PHP spaceship operator (combined comparison operator)

PHP 7’s newly added spaceship operator (combined comparison operator) is used to compare two expressions $a and $b. If $a is less than, equal to, or greater than $b, it returns -1 and 0 respectively. or 1.

Example

<?php
// 整型比较
print( 1 <=> 1);print(PHP_EOL);
print( 1 <=> 2);print(PHP_EOL);
print( 2 <=> 1);print(PHP_EOL);
print(PHP_EOL); // PHP_EOL 为换行符

// 浮点型比较
print( 1.5 <=> 1.5);print(PHP_EOL);
print( 1.5 <=> 2.5);print(PHP_EOL);
print( 2.5 <=> 1.5);print(PHP_EOL);
print(PHP_EOL);

// 字符串比较
print( "a" <=> "a");print(PHP_EOL);
print( "a" <=> "b");print(PHP_EOL);
print( "b" <=> "a");print(PHP_EOL);
?>

##The execution output of the above program is:

0
-1
1

0
-1
1

0
-1
1

④PHP constant array

Example

<?php// 使用 define 函数来定义数组define('sites', [
   'Google',
   'PHP',
   'Taobao']);print(sites[1]);?>

PHP

⑤PHP Closure::call()

Example

<?php
class A {
    private $x = 1;
}

// PHP 7 之前版本定义闭包函数代码
$getXCB = function() {
    return $this->x;
};

// 闭包函数绑定到类 A 上
$getX = $getXCB->bindTo(new A, 'A'); 

echo $getX();
print(PHP_EOL);

// PHP 7+ 代码
$getX = function() {
    return $this->x;
};
echo $getX->call(new A);
?>

1
1

⑥PHP CSPRNG

string random_bytes ( int $length )

<?php
$bytes = random_bytes(5);
print(bin2hex($bytes));
?>

6f36d48a29

int random_int ( int $min , int $max )

<?php
print(random_int(100, 999));
print(PHP_EOL);
print(random_int(-1000, 0));
?>

723
-64

<?php
interface Logger {
   public function log(string $msg);
}
class Application {
   private $logger;
   public function getLogger(): Logger {
      return $this->logger;
   }
   public function setLogger(Logger $logger) {
      $this->logger = $logger;
   }  
}
$app = new Application;
// 使用 new class 创建匿名类
$app->setLogger(new class implements Logger {
   public function log(string $msg) {
      print($msg);
   }
});
$app->getLogger()->log("我的第一条日志");
?>

我的第一条日志

// PHP 7 之前版本需要使用多次 use
use some\namespace\ClassA;
use some\namespace\ClassB;
use some\namespace\ClassC as C;

use function some\namespace\fn_a;
use function some\namespace\fn_b;
use function some\namespace\fn_c;

use const some\namespace\ConstA;
use const some\namespace\ConstB;
use const some\namespace\ConstC;

// PHP 7+ 之后版本可以使用一个 use 导入同一个 namespace 的类
use some\namespace\{ClassA, ClassB, ClassC as C};
use function some\namespace\{fn_a, fn_b, fn_c};
use const some\namespace\{ConstA, ConstB, ConstC};
?>