Analysis of the calling method of PHP reference, php reference calling_PHP tutorial

Analysis of the calling method of PHP reference, PHP reference calling

The example in this article describes the calling method of PHP reference. Share it with everyone for your reference, the details are as follows:

Example 1:

function test($arr){} 
echo test(&$arr); 

Example 2:

function test(&$arr){} 
echo test($arr); 

Examples 1 and 2 have the same effect.

Example 3:

function &test($arr){return $result;} 
echo &test($a);//有效 
echo test($a);//返回的是值,不是引用 

Summary: References are returned only when & is added before the method name when defining a method and & is added before the method name when calling a method.

Example 4:

$a=$b; 

When neither $a nor $b is reassigned, that is, when no writing operation occurs, it is the same as $a=&$b, which is equivalent to assigning a reference.

Only when $a or $b changes, a copy of the value will be assigned to $a

I hope this article will be helpful to everyone in PHP programming.