note 34288 deleted from language.references by sniper

Note Submitter: ernest@vogelsinger.at ---- References have an interesting side effect in arrays. Check this code snippet: error_reporting(E_ALL); // make notices visible $ar = array(); // this will raise a notice about an undefined index: $test = $ar['sample1']; // why? have a look at the array now: echo '<pre>'; print_r($ar); echo '</pre>'; // you see there's no 'sample' array entry. // this output will be empty: echo "Array content is '$test'<br />"; // assigning to the array will not change the output, as expected: $ar['sample1'] = 'demo'; echo "Array content is '$test'<br />"; // using a reference gives a complete other picture: // this reference assignment will NOT trigger any notice! $test =& $ar['sample2']; // why? have a look at the array now: echo '<pre>'; print_r($ar); echo '</pre>'; // you see the array entry now magically came into existence! // now let's assign some value to it: $ar['sample2'] = 'another demo'; // and the test variable will automagically reference this entry: echo "Array content is '$test'<br />"; Summary: referencing a non-existing array entry will automatically define it and establish a reference to the (initially empty) entry.