php7 增加的新特性和变动
增加了类型声明，可以声明函数参数类型，和函数返回值类型
<?php
declare(strict_types=1);
function add(int $a, int $b): int {
return $a+$b;
}
echo add(1, 2);
echo add(1.5, 2.6);//报错，参数类型不对太空船运算符（组合比较符）
<?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);
?>结果：
0
-1
1
0
-1
1
0
-1
1??判空运算符
<?php
//原写法
$username = isset($_GET['user']) ? $_GET['user'] : '';
//现在
$username = $_GET['user'] ?? '';define() 定义常量数组
<?php
define('ARR',['a','b']);
echo ARR[1];// a
增加AST: Abstract Syntax Tree, 抽象语法树，利于代码重构解耦
PHP5 : PHP代码 -> Parser语法解析 -> OPCODE -> 执行
PHP7 : PHP代码 -> Parser语法解析 -> AST -> OPCODE -> 执行
命名空间引用优化
<?php
// PHP5
use FooLibrary\Bar\Baz\ClassA;
use FooLibrary\Bar\Baz\ClassB;
// PHP7
use FooLibrary\Bar\Baz\{ ClassA, ClassB};
匿名函数的引入
<?php
$message = 'hello';
// 没有 "use"
$example = function () {
var_dump($message);
};
echo $example();
// 继承 $message
$example = function () use ($message) {
var_dump($message);
};
echo $example();
// Inherited variable's value is from when the function
// is defined, not when called
$message = 'world';
echo $example();
// Reset message
$message = 'hello';
// Inherit by-reference
$example = function () use (&$message) {
var_dump($message);
};
echo $example();
// The changed value in the parent scope
// is reflected inside the function call
$message = 'world';
echo $example();
// Closures can also accept regular arguments
$example = function ($arg) use ($message) {
var_dump($arg . ' ' . $message);
};
$example("hello");
$course = '数学';
$func = function ($value,$key)use ($course){
echo $value.$course.$key;
};
$arr = [
1=>1,
2=>2,
3=>3
];
array_walk($arr,$func);
结果：
Notice: Undefined variable: message in /example.php on line 6
NULL
string(5) "hello"
string(5) "hello"
string(5) "hello"
string(5) "world"
string(11) "hello world"
输出"1数学12数学23数学3"预加载
预加载功能是指在服务启动时，未运行任何应用程序代码之前，将一组PHP文件加载到内存中，甚至可以对框架进行预加载，以提高性能。如果对预加载代码进行修改，需要重启服务。
[opcache]
zend_extension=opcache.so
opcache.enable=1
opcache.enable_cli=1
opcache.preload=preload.php类属性的类型支持
<?php
class User
{
private int $id;
public string $name;
}NULL合并赋值运算符
<?php
$arr['a'] ??= 'a';
/*等同于*/ $arr['a'] = $arr['a'] ?? 'a';
$b ??= 'b';
/*等同于*/ $b = $b ?? 'b';简化匿名函数
$adder = fn($x, $y) => $x + $y;
// 等同于
$adder = function ($x, $y) {
return $x + $y;
};
$y = 1;
$fn1 = function ($x) use ($y) {
return $x + $y;
};
// 等同于
$fn2 = fn($x) => $x + $y;
// 新的写法省去了 use, 变得更加简洁新增mb_str_split函数
可为空（Nullable）类型
<?php
function testReturn(): ?string
{
return 'elePHPant';
}
var_dump(testReturn());
function testReturn(): ?string
{
return null;
}
var_dump(testReturn());
function test(?string $name)
{
var_dump($name);
}
test('elePHPant');
test(null);
test();Void 函数
<?php
function swap(&$left, &$right) : void
{
if ($left === $right) {
return;
}
$tmp = $left;
$left = $right;
$right = $tmp;
}
$a = 1;
$b = 2;
var_dump(swap($a, $b), $a, $b);短数组语法（[]）现在作为list()语法的一个备选项
<?php
$data = [
[1, 'Tom'],
[2, 'Fred'],
];
// list() style
list($id1, $name1) = $data[0];
// [] style
[$id1, $name1] = $data[0];
// list() style
foreach ($data as list($id, $name)) {
// logic here with $id and $name
}
// [] style
foreach ($data as [$id, $name]) {
// logic here with $id and $name
}list()现在支持键名
<?php
$data = [
["id" => 1, "name" => 'Tom'],
["id" => 2, "name" => 'Fred'],
];
// list() style
list("id" => $id1, "name" => $name1) = $data[0];
// [] style
["id" => $id1, "name" => $name1] = $data[0];
// list() style
foreach ($data as list("id" => $id, "name" => $name)) {
// logic here with $id and $name
}
// [] style
foreach ($data as ["id" => $id, "name" => $name]) {
// logic here with $id and $name
}支持为负的字符串偏移量
<?php
var_dump("abcdef"[-2]);
var_dump(strpos("aabbcc", "b", -3));多异常捕获处理
<?php
try {
// some code
} catch (FirstException | SecondException $e) {
// handle first and second exceptions
}
http2部分支持
允许重写抽象方法
<?php
abstract class A
{
abstract function test(string $s);
}
abstract class B extends A
{
// overridden - still maintaining contravariance for parameters and covariance for return
abstract function test($s) : int;
}
