Importing user data as PHP variables -

i have data file users upload section comprising of keys , values separated tabs , line breaks:

key     value city    london year    1984 

i import script, assign php variables names equal value:

$key = 'value'; $city = 'london'; $year = 1984; 

this used populate templates they've uploaded.

this script assigns keys , values:

$userdata = explode("\n", $file); foreach($userdata &$line){     list($key, $value) = explode("\t", $line);     $$key = $value;} 

i'm wondering if best way assign keys values, if there security precautions should take such prevent key names, , if there way make key equal array if line has multiple tabs.

i think should this:

<?php $filepointer = @fopen($file, 'r'); while($line = fgets($filepointer)){   $a = preg_split('/\b\s+\b/', $line);   ${$a[0]} = $a[1]; } echo "key:$key; city:$city; year:$year;" ?>