php object : get value of attribute by computed name

How 开发者_JAVA技巧do I access an attribute of an object by name, if I compute the name at runtime?

For instance. I loop over keys and want to get each value of the attributes "field_" . $key.

In python there is getattribute(myobject, attrname).

It works, of course, with eval("$val=$myobject->".$myattr.";"); but IMO this is ugly - is there a cleaner way to do it?

Keep always in mind that a very powerful feature of PHP is its Variable Variables

You can use

$attr = 'field' . $key;
$myobject->$attr;

or more concisely, using curl brackets

$myobject->{'field_'.$key};

$myobject->{'field_'.$key}

$val = $myobject->$myattr;

With reflection:

$reflectedObject = new ReflectionObject($myobject);
$reflectedProperty = $reflectedObject->getProperty($attrName);
$value = $reflectedProperty->getValue($myobject);

This works only if the accessed property is public, if it's protected or private an exception will occurr.

I know this is an old subject, but why not just use magic methods?

$myObj->__get($myAttr)