adding to existing session

[eluser]nuttynibbles[/eluser]
okie this is what i did.

1. i created a session in page1.php

Code:

$sessiontag=array('sessiontag'=>array('sessiontagid'=>'abc123')

2. then page1.php will be redirected to page2.php

3. in page2.php, i have a button to insert session values of unique key and the new value. this is what i did:

Code:

/*controller*/
//when button is pressed to insert new value
if($this->input->post('postvalue')=="2"){
//generate unique id
$uniqueid=uniqueid(date('Y-m-d h:i:s:u'),'helloworld');
insertsession('sessiontag',$this->session->userdata('sessiontag'),$uniqueid);
}

/*external function*/
function insertsession($sessid="",$sessionarray="",$uniqueid="")
{
if(!$sessid && !$sessionarray && !$uniqueid)
  return;
          
$sessionnew=array();

foreach($sessionarray as $k=>$v){
//dont overwrite sessiontagid = abc123
if($k=='sessiontagid'){
   $sessionnew[$k]=$v;
   continue;              
  }
//update the existing value
if($k==$uniqueid)
  $sessionnew[$k]="update value";
//insert new array value to session
if($k!=$uniqueid)
  $sessionnew[$uniqueid]="new value";
}
$sessionnew=array('sessiontag'=> $sessionnew);
$this->session->set_userdata($sessionnew);
}

3. each time i did an insert, i realized the unique key and value were overwritten. it did not add a new array. why is this so?

thanks help.