Using the equal sign (
=) copies the value from one variable to another so they both have their own copy of the value. Another option here is to use references, which is where a variable does not have a value of its own; instead, it points to another variable. This enables you to share values and have variables mutually update themselves.
To copy by reference, use the
& symbol, as follows:
<?php $a = 10; $b = &$a; echo $a . "\n"; echo $b . "\n"; $a = 20; echo $a . "\n"; echo $b . "\n"; $b = 30; echo $a . "\n"; echo $b . "\n";?>
If you run that script, you will see that updating
$a also updates
$b, but also that updating