New features of PHP7

New operator
1 、??
$username = $_get[' user ']?? ‘‘;
$username = isset ($_get[' user ')? $_get[' user ']: ' nobody ';

2. <=>
$number 1 <=> $number 2; Returns -1,0,1 when $number 1 is less than, equal to, greater than $number 2 o'clock

New function
Intdiv (dividend, divisor)-Rounding the result of the division
Intdiv (3, 2)//1

Define can define an array
Define (' ANIMALS ', [
' Dog ',
' Cat ',
' Bird '
]);

return type declaration
function test (): int
{
return 1; True
Return ' 1 '; True
Return ' string '; False
}

scalar type declaration
function test (string $name): int
{
return;
}
String Integer Float boolean

can catch core errors
Error hierarchy
Throwable
Error
Arithmeticerror
Divisionbyzeroerror

Assertio Nerror
ParseError
TypeError

Exception


Core Sort optimization
Php5:array (1=>0, 0=>0)//Quick sort (unstable Ordered)
Php7:array (0=>0, 1=>0)//Quick sort + Select sort (Stable sort)



More abstract syntax than PHP5 (abstract snytax tree) AST
Parser, AST->opcodes, PHP, execution
Performance increased, memory consumption increased but negligible


Anonymous classes can instantiate an anonymous class with new class
Function Getanonymousclass ($config) {
Return new Class ($config) {};
}



Temporarily binds a method to the object and calls
$f = function () {
P ($this->name);
};

Class F {
Private $name = ' F ';
}

$f->call (new F);




Unified syntax Variables
Parentheses do not affect behavior from left to right

$a = ' B ';
$b = [' 1 ', ' 2 ', ' 3 '];
Var_dump ($ $a [1]);
Var_dump (($ $a) [1]);

PHP5:
notice:uninitialized string offset:1 in E:\Program files\phpstudy\www\test.php on line 4
notice:undefined variable:in E:\Program files\phpstudy\www\test.php on line 4
Null

Parse error:syntax error, unexpected ' [' E:\Program files\phpstudy\www\test.php on line 4

Php7:string (1) "2" string (1) "2"


Expression PHP5 PHP7
$ $foo [' bar '] [' Baz '] ${$foo [' Bar '] [' Baz ']} ($ $foo) [' Bar '] [' Baz ']
$foo $bar [' Baz '] $foo->{$bar [' Baz ']} ($foo, $bar) [' Baz ']
$foo $bar [' Baz '] () $foo->{$bar [' Baz ']} () ($foo, $bar) [' Baz '] ()
Foo:: $bar [' Baz '] () foo::{$bar [' Baz ']} () (foo:: $bar) [' Baz '] ()




About namespaces
Pre PHP 7 Code
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+ Code
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};


Changes to List
1.
List ($array [], $array [], $array []) = [1, 2, 3];
Var_dump ($array);
Php5:array (3) {[0]=> int (3) [1]=> int (2) [2]=> int (1)}
Php7:array (3) {[0]=> int (1) [1]=> int (2) [2]=> int (3)}


2, do not allow the assignment of null values
List () = $a;
List (,,) = $a;
List ($x, List (), $y) = $a;

PHP7 will error Fatal error:cannot use empty list

3. String splitting is no longer supported
$string = "XY";
List ($x, $y) = $string;
Var_dump ($x, $y);

Php5:string (1) "X" string (1) "Y"
Php7:null NULL

Modification of foreach
Variable references that affect the loop of an array
$array = [0];
foreach ($array as & $val) {
Var_dump ($val);
$array [1] = 1;
}
Php5:int (0)
Php7:int (0) int (1)

New features of PHP7