PHP foreach Reference Assignment

When writing code, it is found that a PHP foreach reference assignment can cause unexpected behavior.

　　code example:

  <? PHP          = Array ('a','b','C');         foreach as $k =>&$v)         {        }                Print_r ($arr);          foreach  as $k =$v)        {             }                Print_r ($arr);   

Output Result: Array ([0] = a [1] = b [2] = + c) Array ([0] = a [1] = b [2] + b)   After finding the information, find out the reason. in fact, after the first foreach ends, the array $arr the last element $v the reference remains. When a second foreach loop is made, it is actually three times the third element of the array $arr the second foreach begins execution, each time the array $arr changes as follows:first time: Array ([0] = a [1] = b [2] = = a) second time: Array ([0] = a [1] = b [2] = = b) third time: Array ([0] = a [1] = b [2] = = b) so there will be the final output.  to avoid this, you can cancel the reference after the first foreach is finished: unset ($v). However, to avoid unexpected results, use a foreach reference to assign values sparingly.

PHP foreach Reference Assignment