note 118498 added to language.references

Another example of something to watch out for when using references with arrays. It seems that even an usused reference to an array cell modifies the *source* of the reference. Strange behavior for an assignment statement (is this why I've seen it written as an =& operator? - although this doesn't happen with regular variables). <?php $array1 = array(1,2); $x = &$array1[1]; // Unused reference $array2 = $array1; // reference now also applies to $array2 ! $array2[1]=22; // (changing [0] will not affect $array1) print_r($array1); ?> Produces: Array ( [0] => 1 [1] => 22 // var_dump() will show the & here ) //above was Noted By Dave at SymmetricDesign dot com// //and below is my opinion to this simple problem. // This is an normal referencing problem. when you gain an reference to a memory at some variable. this variable, means "memory itself". (in above example, this would be -> $x = &$array1[1]; // Unused reference) and you've copied original one($array1) to another one($array2). and the copy means "paste everything on itself". including references or pointers, etcs. so, when you copied $array1 to $array2, this $array2 has same referencers that original $array1 has. meaning that $x = &$array1[1] = &$array2[1]; and again i said above. this reference means "memory itself". when you choose to inserting some values to $array2[1], $x; reference is affected by $array2[1]'s value. because, in allocated memory, $array2[1] is a copy of $array1[1]. this means that $array2[1] = $array1[1], also means &$array2[1] = &$array1[1] as said above. this causes memory's value reallocation on $array1[1]. at this moment. the problem of this topic is cleared by '$x', the memory itself. and this problem was solved by unsetting the '$x'. this is what that bug(clearly, it's not a bug. it's just a missunderstanding) has triggered by. this topic was posted 7 years ago, but i just want to clarify that it's not a bug. if there's some problems in my notes, plz, note that on above. ---- Server IP: 72.52.91.14 Probable Submitter: 203.233.95.248 ---- Manual Page -- http://php.net/manual/en/language.references.php Edit -- https://master.php.net/note/edit/118498 Del: integrated -- https://master.php.net/note/delete/118498/integrated Del: useless -- https://master.php.net/note/delete/118498/useless Del: bad code -- https://master.php.net/note/delete/118498/bad+code Del: spam -- https://master.php.net/note/delete/118498/spam Del: non-english -- https://master.php.net/note/delete/118498/non-english Del: in docs -- https://master.php.net/note/delete/118498/in+docs Del: other reasons-- https://master.php.net/note/delete/118498 Reject -- https://master.php.net/note/reject/118498 Search -- https://master.php.net/manage/user-notes.php