My arrays are strings. Each elements is one line from a file. This is how I read the data and insert it into 2 arrays:

$infile1 = "sept13.csv";
$infile2 = "sept14.csv";
        
open (infile1);
@array1=<infile1>;
close(infile1);
        
open (infile2);
@array2=<infile2>;
close(infile2);
[download]

The format of file(.csv) is as follows. 

Last Name, First Name, WebCT ID, Password, Courses
Calvert,Aaron,aacalvert,0120015,lib101                    
Accardo,Andrea,aaccardo,0110659,biol361h:cost280h:lib100
[download]