Hi, I have tried putting print $OUT1 "$_\n" for @data1; as what netwallah suggested. It is able to print the output I want. But in the command line, it shows: 
Processing data...
Original.txt

Writing output...Use of uninitialized value $metabolite[44] in string 
+at
        G:\Metabolomics\Programming\PERL\Ratio Test\ratio test (update
+d 12 feb 1
4).pl line 101, <CURINFILE> line 1 (#1)
    (W uninitialized) An undefined value was used as if it were alread
+y
    defined.  It was interpreted as a "" or a 0, but maybe it was a mi
+stake.
    To suppress this warning assign a defined value to your variables.

    To help you figure out what was undefined, perl will try to tell y
+ou the
    name of the variable (if any) that was undefined. In some cases it
+ cannot
    do this, so it also tells you what operation you used the undefine
+d value
    in.  Note, however, that perl optimizes your program and the opera
+tion
    displayed in the warning may not necessarily appear literally in y
+our
    program.  For example, "that $foo" is usually optimized into "that
+ "
    . $foo, and the warning will refer to the concatenation (.) operat
+or,
    even though there is no . in your program.


Writing output...Uncaught exception from user code:
        Error couldn't create new Directory at G:\Metabolomics\Program
+ming\PERL\
Ratio Test\ratio test (updated 12 feb 14).pl line 98, <CURINFILE> line
+ 2.
 at G:\Metabolomics\Programming\PERL\Ratio Test\ratio test (updated 12
+ feb 14).p
l line 98
Press any key to continue . . .

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is it some kind of error? In addition, how do I actually loop from dataR1 to dataR3 to put into different arrays instead of having to type out manually as different files has different number of dataRx. I know it has something to do with this line: =~ /_data(\d+)R/ somewhere in the code but I have no idea how. 
            push(@data1, $columns[1]);
            push(@data2, $columns[2]);
            push(@data3, $columns[3]);

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into something like this after finding the /_dataS(\d+)R/ in the column headers: 
push (@data[j], $columns[j]);

[download]
I appreciate if there is any link related to that that can push me to the right direction. :) Thanks for the help by the way!

In reply to Re: How to add column into array from delimited tab file by hellohello1
in thread How to add column into array from delimited tab file by hellohello1

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