PHP learning log - variable scope, variables_PHP tutorial

php learning log - variable scope, variable

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, it cannot be used

PHP stores all global variables in an array called $GLOBALS[index]. index saves the name of the variable. This array can be accessed inside the function or used directly to update global variables. Such as $GLOBALS['y']=$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();

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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.