How to access dynamic property by using variable?

问题

See:

$class_members = get_class_vars(__CLASS__);

foreach($class_members as $key => $value)
{
    if (strpos($key, '_output') === 0)
    {
        // I want to eval() this
        $code = '$this->' . $key . ' = 0;';
    }
}

Assume I want to assign the value 0 to all class members that begin with _output. I plan to use eval. Good or bad idea?

回答1:

You don't need eval() for this. You can use a variable as in $this->{$key}:

foreach($class_members as $key => $value)
{
    if (strpos($key, '_output') === 0)
    {
        // Look mom, no eval()!
       $this->{$key} = 0;
    }
}

回答2:

You can just do:

$this->{$key} = 0;

There are only a few situations where eval isn't considered evil.

And this isn't one of them :)

来源：https://stackoverflow.com/questions/8137552/how-to-access-dynamic-property-by-using-variable