php5.3/5.4/5.5/5.6/7常见新增特性汇总整理

<?php
$cur = $cur ? $cur : 1;
$cur = $cur ?: 1;

<?php
$test = function() {
  echo 'test';
};
$test();

$arr = array(1, 2, 3, 4, 5);
$arr = array_map(function($n) {
  return $n * 2;
}, $arr);
print_r($arr);

<?php
namespace Test;

class Person {
  public function say() {
    echo 'hello';
  }
}
$p = new \Test\Person();
$p->say();

<?php
class A {
  public static function who() {
    echo __CLASS__;
  }
  public static function test() {
    //self::who();
    //static来引用当前的类，这里调用的是B类的静态方法who
    static::who();
  }
}
class B extends A {
  public static function who() {
    echo __CLASS__;
  }
}
//B类调用继承于A的静态方法test，但该方法中self已经绑定了A类，所以调用的是父类的who方法。
//而新增的static则引用当前类，调用的则是本类的who方法。
B::test();

<?php
for($i = 0; $i < 100;   $i) {
  if($i == 50) {
    goto end;
  }
}
end : echo $i;

<?php
class A {
  public static function __callStatic($name, $arguments) {
    echo '你调用了不存在的静态方法:', $name;
  }
  public function __invoke($i) {
    echo '你把对象当函数调用了,还传了个值:', $i;
  }
}
A::xxx();
$a = new A();
$a(6);

<?php
$name = 'test';

//nowdoc使用单引号，内容不做变量解析
$a = <<< 'TEST'
测试$name
TEST;

//heredoc不加引号或加双引号，内容做变量解析
$b = <<< TEST
测试$name
TEST;

echo $a;
echo $b;

<?php
const PI = 3.14;

<?php
class A {
  public static function test() {
    echo 'test';
  }
}
$cName = 'A';
$mName = 'test';
$cName::$mName();

<?php
$arr = array(1, 2, 3);
$arr = array('a' => 1, 'b' => 2);

$arr = [1, 2, 3];
$arr = ['a' => 1, 'b' => 2];

<?php
function getArr() {
  return array(1, 2, 3, 4, 5);
}
echo getArr()[2];

<?php
class A {
  public function test() {
    echo 'test';
  }
}
(new A())->test();

<?php
$arr = array(
  'name' => '哈哈',
  'age' => 25,
);
echo json_encode($arr, JSON_UNESCAPED_UNICODE);

<?php
$bin = 0b101;
echo $bin;

<?php
trait A {
  public function fly() {
    echo '会飞';
  }
}
trait B {
  public function swim() {
    echo '游泳';
  }
}
class People {
  use A, B;
}
(new People())->fly();

<?php
var_dump(empty(3 * 3));

function test() {
  return false;
}
var_dump(empty(test()));

<?php
$arr = function() {
  for($i = 0; $i < 10;   $i) {
    //变量$i的值在不同的yield之间是保持传递的
    yield $i;
  }
};
$data = $arr();
foreach($data as $v) {
  echo $v;
}

<?php
try {
  throw new Exception('我是异常');
} catch(Exception $e) {
  echo $e->getMessage();
} finally {
  echo 'finally';
}

<?php
$arr = array(
  array('name' => 'test1', 'age' => 22),
  array('name' => 'test2', 'age' => 23),
  array('name' => 'test3', 'age' => 24),
);
//取出name列
print_r(array_column($arr, 'name'));
//取出name列，并用age作键
print_r(array_column($arr, 'name', 'age'));

<?php
$arr = [
  [3, 3],
  [4, 4],
  [5, 5],
];
foreach($arr as list($a, $b)) {
  echo $a, '-', $b, '<br>';
}

<?php
const ONE = 1 * 1;
class A {
  const TWO = 1 * 2;
  const THREE = self::TWO   1;
  
  public function test($i = self::THREE   ONE) {
    echo $i;
  }
}
(new A())->test();

<?php
function total(...$nums) {
  $total = 0;
  foreach($nums as $num) {
    $total  = $num;
  }
  return $total;
}
echo total(1, 2, 3, 4, 5);
$arr = [3, 4, 5, 6];
echo total(...$arr);

<?php
echo 2 ** 4;
$a = 2;
$a **= 4;
echo $a;

<?php
namespace A {
  const PI = 3.14;
  function test() {
    echo 'test';
  }
}
namespace B {
  use function \A\test;
  use const \A\PI;
  
  echo PI;
  test();
}

<?php
class A {
  protected $a = 1;
  protected $b = 2;
  protected $c = 3;
  public function __debugInfo() {
    //返回值必须是数组
    return array(
      'a' => $this->a,
    );
  }
}
var_dump((new A()));

<?php
$page = $_GET['page'] ?? 1;

<?php
declare(strict_types=1);

function add(int $num1, int $num2) : int {
  return $num1   $num2;
}
echo add(2, 3);
//在严格模式下，下面这行会报错
echo add(2.0, 3.0);

<?php
(new class {
  public function test() {
    echo 'test';
  }
})->test();

<?php
define('ARR', ['a', 'b', 'c']);
echo ARR[2];