Comparison of PHP pass by value and pass by reference

illustrate

1. In passing by value, PHP must copy the value. Especially for large strings and objects, this will be an expensive operation.

2. Passing by reference does not require copying the value, which is beneficial to performance improvement.

Example

pass by value

 $a = "test";
$b = $a;
$a = "newtest";
echo $a; //output newtest
echo $b; //Output test
--or $a = "test";
$b = $a;
$b = "newtest";
echo $a; //Output test
echo $b; //output newtest

pass by reference

 $a = 'test';
$b = &$a; //Reference assignment, $a and $b point to the same space, and they are relative to a community $b = 'newtest'; //If $b changes, $a will change accordingly echo $a; // output newtest
echo $b; //output newtest

The above is a comparison of PHP pass by value and pass by reference. I hope it will be helpful to everyone.