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copied!<p>First time through the loop</p> <pre><code>foreach($arr as $k=>$v){ // Sets $v to a value of "one" $v =& $arr[$k]; // Sets $v as a reference to $arr[1] ("one") $v .= $k; // Sets $v (and hence also $arr[1]) to "one1" </code></pre> <p>Second time through the loop</p> <pre><code>foreach($arr as $k=>$v){ // Sets $v to a value of "two"... // because $v is already set as a reference to $arr[1] from the previous loop, // this changes $arr[1] to a value of "two" $v =& $arr[$k]; // Sets $v as a reference to $arr[2] ("two") // It no longer references $arr[1] so $arr[1] will not be changed any further $v .= $k; // Sets $v (and hence also $arr[2]) to "two2" </code></pre> <p>Third time through the loop</p> <pre><code>foreach($arr as $k=>$v){ // Sets $v to a value of "three"... // because $v is already set as a reference to $arr[2] from the previous loop, // this changes $arr[2] to a value of "three" $v =& $arr[$k]; // Sets $v as a reference to $arr[3] ("three") // It no longer references $arr[2] so $arr[2] will not be changed any further $v .= $k; // Sets $v (and hence also $arr[3]) to "three3" </code></pre> <p><strong>If you use the unset()</strong></p> <p>First time through the loop</p> <pre><code>foreach($arr as $k=>$v){ // Sets $v to a value of "one" $v =& $arr[$k]; // Sets $v as a reference to $arr[1] ("one") $v .= $k; // Sets $v (and hence also $arr[1]) to "one1" unset($v); // Unsets $v as a reference, it no longer points to $arr[1] </code></pre> <p>Second time through the loop</p> <pre><code>foreach($arr as $k=>$v){ // Sets $v to a value of "two"... // As $v is no longer set as a reference to $arr[1], // this leaves $arr[1] unchanged by this loop $v =& $arr[$k]; // Sets $v as a reference to $arr[2] ("two") $v .= $k; // Sets $v (and hence also $arr[2]) to "two2" unset($v); // Unsets $v as a reference, it no longer points to $arr[2] </code></pre> <p>Third time through the loop</p> <pre><code>foreach($arr as $k=>$v){ // Sets $v to a value of "three"... // As $v is no longer set as a reference to $arr[2], // this leaves $arr[2] unchanged by this loop $v =& $arr[$k]; // Sets $v as a reference to $arr[3] ("three") $v .= $k; // Sets $v (and hence also $arr[3]) to "three3" unset($v); // Unsets $v as a reference, it no longer points to $arr[3] </code></pre>

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