php learning log - variable scope

1. Access global variables within the global function

<?<span>php
</span><span>$x</span>=5<span>;
</span><span>$y</span>=10<span>;

</span><span>function</span><span> myTest()
{
</span><span>global</span><span>$x</span>,<span>$y</span><span>;
</span><span>$y</span>=<span>$x</span>+<span>$y</span><span>;
}

myTest();
</span><span>echo</span><span>$y</span>; <span>//</span><span> 输出 15</span>?>

If global is not used in the myTest function, you cannot use

PHP to store all global variables in an array named $GLOBALS[index] . index Save the name of the variable. This array can be accessed inside the function or used directly to update global variables. For example, $GLOBALS['y']=$GLOBALS['x']+$GLOBALS['y']

2. Static When a function is completed, all its variables are usually deleted. However, sometimes you want a local variable not to be deleted.

function myTest()
{
static $x=0;
echo $x;
$x++;
}

myTest();
myTest();
myTest();

0
1
2

　Every time the function is called, the variable will retain the value when the function was called last time. The variable remains local to the function.

The above introduces the PHP learning log - variable scope, including the content of global variables. I hope it will be helpful to friends who are interested in PHP tutorials.