Some of important PHP 7.* features

New PHP features let the code to be safer, faster and less error prone.

PHP 7.0 to PHP 7.3:

• Spaceship operator: <=>

// if first operator is correct it returns -1, second 0 and third +1
echo 1 <=> 2; // -1
echo 1 <=> 1; // 0
echo 2 <=> 1; // 1

• intdiv: integer division

echo intdiv(10, 3); // 3

• Type hinting
• Group Use Declarations:

use FooLibrary\Bar\Baz\{ ClassA, ClassB, ClassC as Fizbo }

• Return Type Declarations
• Multi catch
• Void Return Type; no return or just return; NULL is not a valid return value for a void function
• Nullable types:

function test(?string $name){
    var_dump($name);
}

• Argon2 in password hash
• Null checking operator: ??
• const array using define
• safe unserialize for untrusted data using whitelist classes
• NULL is not a valid return value for a void function
• Support for negative string offsets:

"abcdef"[-2] // 'e'

• New object type:

function test(object $obj) : object {
  return new SplQueue();
}

PHP 7.4:

• Preloading: Preload PHP functions and classes once and use them in the context of any future request without overhead
• Declare types for class properties; forcing developers to instead use getter and setter methods
• Weak refs: allow keeping a reference to an object and preventing the object from being destroyed

• Null Coalescing Assignment Operator:

  $data['comments']['user_id'] ??= 'value';
  

PHP 8.0:

• Just in Time Compiler:
  • Let the codes run directly by CPU
  • Improves speed of applications which use a lot of CPU time
  • Great for machine learning, data analysis,… applications
  • It doesn’t speed up much I/O bound applications