On the new characteristics of PHP7

The highest version of PHP I've ever used is php5.6. After a new job, the company is using PHP7. It is said that PHP7 's performance is much higher than before. The following is a new feature of PHP7. Strive for a simple understanding. Do not do in-depth research.

1. Variable type declaration

• When the parameters of a function use strict mode, an exception is returned if the incoming parameter data type is inconsistent TypeError
• The data types that can be declared are: Class/interface, self, array, callback, bool, float, int, string. [Reference-function parameters] (http://php.net/manual/zh/functions.arguments.php#functions.arguments.type-declaration)

2. Added a return value type declaration.

• You can now specify the data type of the function's return value.
• The return value declares the type, which refers to the variable type declaration.

function hasReturn() : bool{}

3.null Merge Operators

• That's a good feature. Many ternary expressions +isset () can be written in this way.
• Null merge operator: If the variable exists and the value is not NULL, it returns its own value, otherwise it returns its second operand. Much like MySQL's Ifnull ().

$value = $_GET[‘memc_codes‘] ?? ‘没使用优惠券啊‘;

4. Spaceship operator

• Used to compare two expressions, to determine the size relationship between them, less than, equal to, or greater than the return -1,0,1 respectively.

echo 1 <=> 1;echo 1 <=> 2;echo 2 <=> 1;

5. Defin () can define array constants

• In other words, constants can be defined as an array

6. An anonymous class can be instantiated with the new class

• Anonymous class, you can throw it out.

7. Support for Unicode codepoint Translator 8. Closure::call () temporarily binds a method to an object closure and immediately calls

class A { private $lang = ‘php‘;}$getLang = function() { return $this->lang；}；echo $getLang->call(new A); // 暂时将getLang函数绑定到A上，并执行它

9. Unserialize () The second parameter can filter the deserialized data

• Prevent Code injection

10. Added Intlchar to manipulate Unicode character 11 for multi-character sets. ASSERT () increase, write codeception more convenient

• ASSERT () is now a language structure. The first one can be an argument is an expression.

12. One use can import multiple classes

use model\A,B,C;

13. The generator can return an expression and get the value of the generator by calling the Generator::getreturn () method.

$gen = (function(){    yield 1;    return 3;})();foreach ($gen as $val) {    echo $val,PHP_EOL;}echo $gen->getReturn(),PHP_EOL; ## 这里

14. The yield from the generator can be used to introduce other generators

function gen() {    yield 1;    yield from gen2();}function gen2() {    yield 3;    yield 4;}froeach ($gen as $val) {    echo $val,PHP_EOL;}

15. New addition of normal function intdiv ()

echo intdiv(10,3); // 3

Session_Start () New parameter can modify system setting value

• This deserves a closer look. Session options

17. Add Preg_replace_callback_array () function, you can pass multiple anonymous functions into the array. More concise than Preg_replace_callback (). 18. Add Random_bytes () and Random_int () to facilitate random number 19. You can use the list () function to expand an object that implements the Arrayaccess interface

On the new characteristics of PHP7