What is this error?

[lenora]

Notice: Undefined index: 27 in /var/www/html/johnsonpublishing.com/webadmin/members/members_list.html on line 456


This is line 456
$lists_display[] = $lists_array["$lists_ID"];

Here is the entire code
if ($lists != "") {
$lists_display = Array();
$lists = explode(",", $lists);
foreach($lists AS $lists_ID) {
if ($lists_ID != "") {
$lists_display[] = $lists_array["$lists_ID"];

[clamcrusher]

its kinda like an undefined variable notice, except its saying the array element is undefined.

given the following array

$array = array(
   'foo' => 5,
    'bar' => 5
);

// works, because $array['foo'] exists
echo $array['foo'];


// generates undefined index notice
echo $array['lenora']; 

using $array['lenora'] gives the undefined index notice, because there is no 'lenora' element in the array to use.


you can use isset() or array_key_exists() to check if a variable/array element exists. they have slightly different behavior, the php manual explains the difference.

[lenora]

Since it doesn't exist why can't I take it out?

[Dan Grossman]

The error means that on this line

$lists_display[] = $lists_array["$lists_ID"]; 

$lists_ID is equal to some value that's not in $lists_array.

Since I can't see the source of the $lists variable that populated $lists_array, I can't tell you where or how you could take out whatever's not being found. As clamcrusher said, you would use array_key_exists() to see if $lists_ID is in $lists_array before assigning it to $lists_display if you want to avoid this notice.

[lenora]

I've been working on the file for two days now and its still is not right, may I send you the source file so you can tell me what it is I am doing wrong?