PHP beginner - issues with associative arrays - php

Question

I'm trying to take a file of id numbers and find the names associated with those numbers from a different file and print a csv in the form id,name.
The Def.csv file is in the form
1;128;34;64;Uppland,
2;0;36;128;Östergötland,
3;128;38;192;Småland,
WIth the first number being the ID and the last field the name.
The IDs.csv is just IDs in no specific order with a comma and new line. ie.
12, \n
Here's the (updated, bad) script:
<?php
$ID;
$names;
$both = array();
$row = 0;
echo ("1\n");
if (($handle = fopen("IDs.csv", "r+")) !== FALSE) {
while (($data = fgetcsv($handle, 1000, ",")) !== FALSE) {
$ID[$row] = $data[0];
$row++;
//print_r($ID);
}
}
print_r($ID);
fclose($handle);
if (($handle = fopen("Defs.csv", "r+")) !== FALSE) {
while (($data = fgetcsv($handle, 1000, ";")) !== FALSE) {
$Names = $data[4];
// DEBUG, works// echo "$Names";
}
}
fclose($handle);
for ($c = 0; $c < $row; $c++)
{
$Both[$ID[$c]] = $Names[$ID[$c]];
}
foreach ($Both as $key => $value)
{
echo "$key,$value\n";
}
?>
This is my current output
Array
(
[0] => 2
[1] => 3
[2] => 1
)
2,t
3,l
1,u
for the small test case here it should be 2,Östergötland 3,Småland and 1,Uppland