Introduction to new expression constants and keywords in php7

The project I did recently used php7, but I feel that there are many new features that are not used. Just want to summarize some new features that may be used. The environment I used before was php5.4, and all the features of php5.5 and php5.6 will be summarized. Here I only list the features that I think may be used in the project. The main content comes fromphp manualAppendix.

Generators (PHP 5 >= 5.5.0, PHP 7)

Generators are supported by adding the yield keyword. Generators provide a simpler way to implement iterators without implementing the Iterator interface.

      
The above routine will output:
      
Single digit odd numbers: 1 3 5 7 9

      
Click for detailsGenerator
      
Added finally keyword (PHP 5 >= 5.5.0, PHP 7)
##try-catch now supports finally
      

      
foreach now supports list() (PHP 5 >= 5.5.0, PHP 7)
The foreach control structure now supports separating nested arrays into separate ones via the list() construct Variables. For example:
      

      

      
The above routine will output:
      
A: 1; B: 2
      
A: 3; B: 4


      
array_column(PHP 5 >= 5.5.0, PHP 7)
array_column — Returns a specified column in an array
      

      
UseExpressionDefine constants (PHP 5 >= 5.6.0, PHP 7)
In previous PHP versions, static values must be used to define constants. Declare properties and specify
      
function parametersdefault values. You can now use numeric expressions including numbers,stringliterals, and other constants to define constants, declare properties, and set default values for function parameters.
      
f()."\n"; echo C::SENTENCE; ?>
      
The above routine will output:
      
4
      

The value of THREE is 3
      

Now you can pass the const keyword to define a constant of type array.
      

      

      
The above routine will output:
      
a
      


      
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