Help needed: array save then edit later

[datona]

I have a form that gets saved to a mysql database.
This is an example of the mutiple checkbox array in the register form:

<input type="checkbox" name="Hobbies[]" value="Antiques" <?php if ($Hobbies[0] == "Antiques") echo "CHECKED" ?>>
<input type="checkbox" name="Hobbies[]" value="Dogs" <?php if ($Hobbies[1] == "Dogs") echo "CHECKED" ?>>
<input type="checkbox" name="Hobbies[]" value="Motorcycles" <?php if ($Hobbies[2] == "Motorcycles") echo "CHECKED" ?>>
<input type="checkbox" name="Hobbies[]" value="Social cause/activism" <?php if ($Hobbies[3] == "Social cause/activism") echo "CHECKED" ?>>

When saving the form, I have this:

$new_Hobbies = implode(",", $_POST['Hobbies']);

Then I save $new_Hobbies in a field of the MySQL table.

When it comes to a client EDITING there information, again I am bringing that information up as:

$Hobbies=explode(",", $new_Hobbies);

<input type="checkbox" name="Hobbies[]" value="Antiques" <?php if ($Hobbies[0] == "Antiques") echo "CHECKED" ?>>
<input type="checkbox" name="Hobbies[]" value="Dogs" <?php if ($Hobbies[1] == "Dogs") echo "CHECKED" ?>>
<input type="checkbox" name="Hobbies[]" value="Motorcycles" <?php if ($Hobbies[2] == "Motorcycles") echo "CHECKED" ?>>
<input type="checkbox" name="Hobbies[]" value="Social cause/activism" <?php if ($Hobbies[3] == "Social cause/activism") echo "CHECKED" ?>>

----PROBLEM----

What is currently happening is that IF the client when registering chooses:
Checkbox 1
Checkbox 2
Checkbox 4
The only boxes that are checked in the edit page is checkbox 1 and 2. Checkbox 4 is not checked.

It seems to fill-in the form fine UNTIL it comes to a blank and then stops showing the checkboxes checked.

Inside the new_Hobbies field is the following:
Antiques,Dogs,Social cause/activism
You will see that since the client DID NOT choose 'Motorcycles', it is not in the database.

Why does it stop at checkbox 3 and not update checkbox 4?
This is driving me crazy.

Any help would be greatly appreciated. Thanks

[dalecosp]

When the user selects boxes 1, 2, and 4, you are putting them into locations 0, 1, 2 of your array. When you do your == checking, the [2] element is not "Motorcycles", it's "activism" and the [3] element is blank....

Easy to diagnose, but it's too late for me to think of a quick fix....you may need to rethink your input process...but like I said, I'm tired & not thinking too straight...

Maybe you could send a blank value for the elements they don't check...