There are many differences between PHP 5 and 7. Some of the main points are:
Performance:
PHP 7: Performance speed is double. Average requests per second are 44 when it is 22 in php5.
PHP 5: Performance is low compared to php7.
Return Type: In PHP 5, the programmer is not allowed to define the type of return value of a function which is the major drawback. But in PHP 7, this limitation is overcome and a programmer is allowed to define the return type of any function.
Error handling: In PHP 5, there is high difficulty to manage fatal errors but in PHP 7, some major errors are replaced by exceptions which can be managed effortlessly. In PHP 7, the new engine Exception Objects has been introduced.
64-bit support: PHP 5 doesn’t support 64-bit integer while PHP 7 supports native 64-bit integers as well as large files.
Anonymous Class:
PHP 7: A developer can create an anonymous class for a one-off use, rather than creating a full definition of a class that is required only once in the entire application.
PHP 5: There is no concept of anonymous classes.
New Operators: Some new operators have added in PHP 7 such as <=> which is called a three-way comparison operator. Another operator has added is a null coalescing operator which symbol as?? and use to find whether something exists or not.
Group Use declaration: PHP 7 includes this feature whereas PHP 5 doesn’t have this feature.
Null Coalesce Operator:
The coalesce operator (??) returns a result of its first operand if it exists, or null if it doesn’t. Example. :
In PHP 5:
if (isset ($_GET ['id']))
{
$name = $_GET ['id'];
}
else
$name = null;In PHP 7:
$id = $_GET ['id']?? Null;