PHP function for auto increment with changed value

Question

I have a requirement where I need to insert user_id in following format

13310_userid_1
13310_userid_2
13310_userid_3

where

13310 = $_GET['userid'] //user id from session
userid = constant //constant text defined
1/2/3 = autoincrement value

Here the variation is when user_id is changed, the auto increment value will be inserted from beginning which would look like

13311_userid_1
13311_userid_2
13311_userid_2

and not

13311_userid_4
13311_userid_5
13311_userid_6

How can I check if the user_id is changed and insert auto increment value from 1 ?

Thanks

Answer 1

I'm not sure it's that you need, but you can use an array to store increment of each cont :

$const = 'userid';
$user_id = '13310';
$array_increment[$user_id] =1;
foreach(array('Franck','Robert','You','Me') as $index=>$test){
    if($index==2)$user_id = '13311';
    if(!isset($array_increment[$user_id])){
        $array_increment[$user_id]=1;
    }

    $increment = $array_increment[$user_id];

    echo $user_id.'_'.$const.'_'.$increment.'<br />';
    $array_increment[$user_id]++;
}

Will show :

13310_userid_1
13310_userid_2
13311_userid_1
13311_userid_2