php - While-loop, undefined offset -

i "undefined offset" errors, starting index 20 shown in following output:

<b>notice</b>:  undefined offset: 20 in <b>/var/www/sso/html/wp-content/plugins/auto-login/papex-auto-login.php</b> on line <b>214</b><br /> <br /> <b>notice</b>:  undefined offset: 21 in <b>/var/www/sso/html/wp-content/plugins/auto-login/papex-auto-login.php</b> on line <b>214</b><br /> <br /> <b>notice</b>:  undefined offset: 22 in <b>/var/www/sso/html/wp-content/plugins/auto-login/papex-auto-login.php</b> on line <b>214</b><br /> <br /> 

my array $match - below - has 20 indexes. output sql question correct – have checked multiple times. print_r, output foreach loop echo $value->meta_key.

it seems while loop goes through whole $match array, won't terminate. thats why think starts producing "undefined" offsets, starting 20.

what doing wrong; how come – if right – code doesn't exit while loop?

// user id       $db_user_id = $wpdb->get_row("select id $table_users user_email = '$user_email'");  // user result $results = $wpdb->get_results("select * $table_usermeta user_id = '$db_user_id->id'");  $match = array(             "billing_country",             "billing_first_name",             "billing_last_name",             "billing_company",             "billing_address_1",             "billing_address_2",             "billing_city",             "billing_state",             "billing_postcode",             "billing_email",             "billing_phone",             "shipping_country",             "shipping_first_name",             "shipping_last_name",             "shipping_company",             "shipping_address_1",             "shipping_address_2",             "shipping_city",             "shipping_state",             "shipping_postcode" );    foreach($results $value) {      $check = true;       $i = 0;      while($check == true)     {         if($match[$i] == $value->meta_key)         {             echo $i . ' ';             echo ' inne ';             $check = false;             break;         }             $i++;        } } 

you should check if $match[$i] exists. error mesages occur because doesn't.

so, either do:

if(isset($match[$i] && $match[$i] == $value->meta_key) {     ... } 

or replace copmplete part inside foreach loop this:

for($i=0; $i<count($match); $i++) {     if($match[$i] == $value->meta_key) {         ...         break;     } } 

this way make sure never out of bounds.

what did wrong condition leaving while loop ever caught when had match, not when end of array reached (you never tested that).