search
HomeBackend DevelopmentPHP TutorialDetailed examples of new features in PHP7.1 and 7.2

php7.1 New features

1. Nullable type

The type declaration of parameters and return values ​​can be made by adding a question mark () before the type name ?) to mark it as null. Indicates that the type of the function parameter or return value is either the specified type or null.

Look at the example:

function testReturn(?string $name){
    return $name;
}

var_dump(testReturn('yangyi'));
var_dump(testReturn(null));
var_dump(testReturn2());

Print output:

$ php php71.phpstring(6) "yangyi"NULL

PHP Fatal error:  Uncaught ArgumentCountError: 
Too few arguments to function testReturn(), 
0 passed in php71.php on line 22 and exactly 1 
expected in php71.php:14Stack trace:#0 php71.php(22): 
testReturn()#1 {main}
  thrown in php71.php on line 14

Same as above: The third one reported a fatal error.

Let’s look at the situation where the function return value is Nullable:

function testReturn3() : ?string{
    //return "abc";
    //return null;}

var_dump(testReturn3());

If ? is added, either string or null will be returned. You cannot return nothing. An error will be reported.

2.void return type

PHP7.0 added the feature of specifying the function return type, but the return type cannot be specified as void. This feature of 7.1 is a supplement. A function defined with a return type of void cannot have a return value, even if it returns null:

function testReturn4() : void{
    //1. 要么啥都不返还 ok

    //2. 要么只return; ok
    //return;

    //3. return null 也会报错
    //return null;

    //4. return 4 会报错
    //return 4;}
Fatal error: A void function must not return a value in /php71.php on line 70

Also, void can only be used for return values ​​and not for parameters. For example, the following error will be reported:

function testReturn6(void $a) : void{}

var_dump(testReturn6());
PHP Fatal error:  void cannot be used as a parameter type in php71.php on line 73

If a method is declared as void return type in class inheritance, if the subclass inherits and overrides it, it can only return void, otherwise an error will be triggered:

<?php class Foo{
    public function bar(): void {
    }
}class Foobar extends Foo{
    // 覆盖失败
    public function bar(): array { 
        // Fatal error: Declaration of Foobar::bar() must be compatible with Foo::bar(): void
    }
}

So, you must do this, so you won’t report an error:

class Foo{
    public $a;    public function bar(): void {
        $this->a = 2;
    }
}class Foobar extends Foo{
    // 覆盖成功
    public function bar(): void {
        $this->a = 3;
    }
}

3.list’s square brackets ([]) abbreviation and adding the specified key

can be used list to quickly traverse to get the values ​​in the array. Now you can use [] abbreviation.

$data = [
    [1, &#39;Tom&#39;],
    [2, &#39;Fred&#39;],
];// list() stylelist($id1, $name1) = $data[0];// [] style[$id1, $name1] = $data[0];// list() styleforeach ($data as list($id, $name)) {    // logic here with $id and $name}// [] styleforeach ($data as [$id, $name]) {    // logic here with $id and $name}

In addition, this updated list can also specify a key for the index array. This upgrade is great and very convenient.

$data = [
    ["id" => 1, "name" => &#39;Tom&#39;],
    ["id" => 2, "name" => &#39;Fred&#39;],
];// list() stylelist("id" => $id1, "name" => $name1) = $data[0];
// [] style["id" => $id1, "name" => $name1] = $data[0];
// list() styleforeach ($data as list("id" => $id, "name" => $name)) {    
// logic here with $id and $name
}
// [] styleforeach ($data as ["id" => $id, "name" => $name]) {    
// logic here with $id and $name}

Before this function was not available, we usually used while + each to traverse the index array using list:

$data = [
    ["id" => 1, "name" => &#39;Tom&#39;],
    ["id" => 2, "name" => &#39;Fred&#39;],
];while (list($id, name) = each($data)) {    
echo "$key => $val\n";
}

Note: The each function has been removed in PHP 7.2! Therefore, do not use this method to traverse the index array

3. Class constant visible range setting

Before, the constants in the class were declared with const , has no visible attributes. Now the visible attributes of the method are transplanted:

<?php 
class ConstDemo 
{    // 常量默认为 public
    const PUBLIC_CONST = 0;    // 可以自定义常量的可见范围
    public const PUBLIC_CONST_B = 2;    protected const PROTECTED_CONST = 3;    
    private const PRIVATE_CONST = 4;    // 多个常量同时声明只能有一个属性
    private const FOO = 1, BAR = 2;
}

The usage method is the same as the method of the class. I won’t go into details.

4. Support negative string offset

There are 2 updates, 1 is to take the string directly, 2 is that the third parameter of strpos function supports negative numbers. Indicates taking from the tail.

var_dump("abcdef"[-2]); // evar_dump(strpos("aabbcc", "b", -3)); //3

The string variable can take the value directly without passing the variable name. It was added in php5.5. Now you can take it from the tail:

var_dump("abcdef"[-2]); // 从末尾取倒数第2个字符:evar_dump("abcdef"[2]); 
// 从前面取第2个,从0开始:c$string = &#39;bar&#39;;echo $string[1], $string[-1]; // a r

5. Multi-condition catch

In the previous try...catch statement, each catch can only set one conditional judgment:

try {    // Some code...} catch (ExceptionType1 $e) {    
// 处理 ExceptionType1} catch (ExceptionType2 $e) {    
// 处理 ExceptionType2} catch (Exception $e) {    // ...}

Now multiple ones can be processed together. Separate with "|".

try {
    // Some code...
} catch (ExceptionType1 | ExceptionType2 $e) {
    // 对于 ExceptionType1 和 ExceptionType2 的处理
} catch (Exception $e) {
    // ...}

php7.2

php 7.2 is mostly a bottom-level update to improve performance. There are not many updates at the common syntax level, so we will skip them here.

I have previously written about the new features and new features of php7.0 and older versions of php. Today let’s take a look at the new features of php7.1 and php7.2.

php7.1 New features

1. Nullable type

The type declaration of parameters and return values ​​can be made by adding a question mark before the type name ( ?) to mark it as null. Indicates that the type of a function parameter or return value is either the specified type or null.

Look at the example:

function testReturn(?string $name){
    return $name;
}

var_dump(testReturn(&#39;yangyi&#39;));
var_dump(testReturn(null));
var_dump(testReturn2());

Print output:

$ php php71.phpstring(6) "yangyi"NULL

PHP Fatal error:  Uncaught ArgumentCountError: 
Too few arguments to function testReturn(), 0 passed in php71.php on line 22 and exactly 
1 expected in php71.php:14Stack trace:#0 php71.php(22): testReturn()#1 {main}
  thrown in php71.php on line 14

Same as above: The third one reported a fatal error.

Let’s look at the situation where the function return value is Nullable:

function testReturn3() : ?string{
    //return "abc";
    //return null;}

var_dump(testReturn3());

If ? is added, either string or null will be returned. You cannot return nothing. An error will be reported.

2.void return type

PHP7.0 added the feature of specifying the function return type, but the return type cannot be specified as void. This feature of 7.1 is a supplement. A function defined with a return type of void cannot have a return value, even if it returns null:

function testReturn4() : void{
    //1. 要么啥都不返还 ok

    //2. 要么只return; ok
    //return;

    //3. return null 也会报错
    //return null;

    //4. return 4 会报错
    //return 4;}
Fatal error: A void function must not return a value in /php71.php on line 70

Also, void can only be used for return values ​​and not for parameters. For example, the following error will be reported:

function testReturn6(void $a) : void{}

var_dump(testReturn6());
PHP Fatal error:  void cannot be used as a parameter type in php71.php on line 73

If a method is declared as void return type in class inheritance, if the subclass inherits and overrides it, it can only return void, otherwise an error will be triggered:

<?php class Foo{
    public function bar(): void {
    }
}class Foobar extends Foo{
    // 覆盖失败
    public function bar(): array { 
        // Fatal error: Declaration of Foobar::bar() must be compatible with Foo::bar(): void
    }
}

So, you must do this, so you won’t report an error:

class Foo{
    public $a;    public function bar(): void {
        $this->a = 2;
    }
}class Foobar extends Foo{
    // 覆盖成功
    public function bar(): void {
        $this->a = 3;
    }
}

3.list’s square brackets ([]) abbreviation and adding the specified key

can be used list to quickly traverse to get the values ​​in the array. Now you can use [] abbreviation.

$data = [
    [1, &#39;Tom&#39;],
    [2, &#39;Fred&#39;],
];// list() stylelist($id1, $name1) = $data[0];// [] style[$id1, $name1] = $data[0];
// list() styleforeach ($data as list($id, $name)) {    // logic here with $id and $name}
// [] styleforeach ($data as [$id, $name]) {    // logic here with $id and $name}

In addition, this updated list can also specify a key for the index array. This upgrade is great and very convenient.

$data = [
    ["id" => 1, "name" => &#39;Tom&#39;],
    ["id" => 2, "name" => &#39;Fred&#39;],
];// list() stylelist("id" => $id1, "name" => $name1) = $data[0];
// [] style["id" => $id1, "name" => $name1] = $data[0];
// list() styleforeach ($data as list("id" => $id, "name" => $name)) {   
 // logic here with $id and $name}// [] styleforeach ($data as ["id" => $id, "name" => $name]) {   
  // logic here with $id and $name}

Before this function was not available, we usually used while + each to traverse the index array using list:

$data = [
    ["id" => 1, "name" => &#39;Tom&#39;],
    ["id" => 2, "name" => &#39;Fred&#39;],
];while (list($id, name) = each($data)) {    echo "$key => $val\n";
}

Note: The each function has been removed in PHP 7.2! Therefore, do not use this method to traverse the index array

3. Class constant visible range setting

Previously, the constants in the class were declared with const , has no visible attributes. Now the visible attributes of the method are transplanted:

<?php 
class ConstDemo 
{    // 常量默认为 public
    const PUBLIC_CONST = 0;    // 可以自定义常量的可见范围
    public const PUBLIC_CONST_B = 2;    protected const PROTECTED_CONST = 3;    private const PRIVATE_CONST = 4;    // 多个常量同时声明只能有一个属性
    private const FOO = 1, BAR = 2;
}

The usage method is the same as the method of the class. I won’t go into details.

4. Support negative string offset

There are 2 updates, 1 is to take the string directly, 2 is that the third parameter of strpos function supports negative numbers. Indicates taking from the tail.

var_dump("abcdef"[-2]); // evar_dump(strpos("aabbcc", "b", -3)); //3

string变量可以直接取值,不用通过变量名,是在php5.5加入的。现在可以从尾部取:

var_dump("abcdef"[-2]); // 从末尾取倒数第2个字符:evar_dump("abcdef"[2]); 
// 从前面取第2个,从0开始:c$string = &#39;bar&#39;;echo $string[1], $string[-1]; 
// a r

5.多条件 catch

在以往的 try … catch 语句中,每个 catch 只能设定一个条件判断:

try {    // Some code...} catch (ExceptionType1 $e) {    
// 处理 ExceptionType1} catch (ExceptionType2 $e) {    
// 处理 ExceptionType2} catch (Exception $e) {    
// ...}

现在可以多个一起处理。用”|” 分割。

try {
    // Some code...
} catch (ExceptionType1 | ExceptionType2 $e) {
    // 对于 ExceptionType1 和 ExceptionType2 的处理
} catch (Exception $e) {
    // ...}

php7.2

php 7.2大都是底层的更新,提高性能。没有太大常用语法层面的更新,这里就略过了。

相关推荐:

谈谈 PHP7新增功能

PHP7新增 功能,php7新增功能

PHP5.2至5.6的新增功能详解

The above is the detailed content of Detailed examples of new features in PHP7.1 and 7.2. For more information, please follow other related articles on the PHP Chinese website!

Statement
The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn
The Continued Use of PHP: Reasons for Its EnduranceThe Continued Use of PHP: Reasons for Its EnduranceApr 19, 2025 am 12:23 AM

What’s still popular is the ease of use, flexibility and a strong ecosystem. 1) Ease of use and simple syntax make it the first choice for beginners. 2) Closely integrated with web development, excellent interaction with HTTP requests and database. 3) The huge ecosystem provides a wealth of tools and libraries. 4) Active community and open source nature adapts them to new needs and technology trends.

PHP and Python: Exploring Their Similarities and DifferencesPHP and Python: Exploring Their Similarities and DifferencesApr 19, 2025 am 12:21 AM

PHP and Python are both high-level programming languages ​​that are widely used in web development, data processing and automation tasks. 1.PHP is often used to build dynamic websites and content management systems, while Python is often used to build web frameworks and data science. 2.PHP uses echo to output content, Python uses print. 3. Both support object-oriented programming, but the syntax and keywords are different. 4. PHP supports weak type conversion, while Python is more stringent. 5. PHP performance optimization includes using OPcache and asynchronous programming, while Python uses cProfile and asynchronous programming.

PHP and Python: Different Paradigms ExplainedPHP and Python: Different Paradigms ExplainedApr 18, 2025 am 12:26 AM

PHP is mainly procedural programming, but also supports object-oriented programming (OOP); Python supports a variety of paradigms, including OOP, functional and procedural programming. PHP is suitable for web development, and Python is suitable for a variety of applications such as data analysis and machine learning.

PHP and Python: A Deep Dive into Their HistoryPHP and Python: A Deep Dive into Their HistoryApr 18, 2025 am 12:25 AM

PHP originated in 1994 and was developed by RasmusLerdorf. It was originally used to track website visitors and gradually evolved into a server-side scripting language and was widely used in web development. Python was developed by Guidovan Rossum in the late 1980s and was first released in 1991. It emphasizes code readability and simplicity, and is suitable for scientific computing, data analysis and other fields.

Choosing Between PHP and Python: A GuideChoosing Between PHP and Python: A GuideApr 18, 2025 am 12:24 AM

PHP is suitable for web development and rapid prototyping, and Python is suitable for data science and machine learning. 1.PHP is used for dynamic web development, with simple syntax and suitable for rapid development. 2. Python has concise syntax, is suitable for multiple fields, and has a strong library ecosystem.

PHP and Frameworks: Modernizing the LanguagePHP and Frameworks: Modernizing the LanguageApr 18, 2025 am 12:14 AM

PHP remains important in the modernization process because it supports a large number of websites and applications and adapts to development needs through frameworks. 1.PHP7 improves performance and introduces new features. 2. Modern frameworks such as Laravel, Symfony and CodeIgniter simplify development and improve code quality. 3. Performance optimization and best practices further improve application efficiency.

PHP's Impact: Web Development and BeyondPHP's Impact: Web Development and BeyondApr 18, 2025 am 12:10 AM

PHPhassignificantlyimpactedwebdevelopmentandextendsbeyondit.1)ItpowersmajorplatformslikeWordPressandexcelsindatabaseinteractions.2)PHP'sadaptabilityallowsittoscaleforlargeapplicationsusingframeworkslikeLaravel.3)Beyondweb,PHPisusedincommand-linescrip

How does PHP type hinting work, including scalar types, return types, union types, and nullable types?How does PHP type hinting work, including scalar types, return types, union types, and nullable types?Apr 17, 2025 am 12:25 AM

PHP type prompts to improve code quality and readability. 1) Scalar type tips: Since PHP7.0, basic data types are allowed to be specified in function parameters, such as int, float, etc. 2) Return type prompt: Ensure the consistency of the function return value type. 3) Union type prompt: Since PHP8.0, multiple types are allowed to be specified in function parameters or return values. 4) Nullable type prompt: Allows to include null values ​​and handle functions that may return null values.

See all articles

Hot AI Tools

Undresser.AI Undress

Undresser.AI Undress

AI-powered app for creating realistic nude photos

AI Clothes Remover

AI Clothes Remover

Online AI tool for removing clothes from photos.

Undress AI Tool

Undress AI Tool

Undress images for free

Clothoff.io

Clothoff.io

AI clothes remover

Video Face Swap

Video Face Swap

Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Tools

MantisBT

MantisBT

Mantis is an easy-to-deploy web-based defect tracking tool designed to aid in product defect tracking. It requires PHP, MySQL and a web server. Check out our demo and hosting services.

Dreamweaver Mac version

Dreamweaver Mac version

Visual web development tools

SublimeText3 Mac version

SublimeText3 Mac version

God-level code editing software (SublimeText3)

PhpStorm Mac version

PhpStorm Mac version

The latest (2018.2.1) professional PHP integrated development tool

WebStorm Mac version

WebStorm Mac version

Useful JavaScript development tools