Text File Parsing - List Unique Column Values

[vinodmalraj]

Am new to perl language , would really help if some of you assist me how to use a regex say for example this is my log file

000046571|1000025|CUSTOMER|27-JUN-2007 06:27:59|005|DEFAULT
000046572|1000026|ACTIVATE|16-JUL-2007 12:33:13|013|DEFAULT
000046572|1000026|ACTIVATE|16-JUL-2007 12:33:13|018|MENU

i want to take only the 6th field(DEFAULT) by using my following perl srcipt

cut -d \| -f6 <filename> | sort | uniq

so that i take only the unique fields(DEFAULT, MENU. etc.) from the log file.

When i run the above command i get duplicate fields also which should not be the case.I guess at the end of every row there is a space so am not able to take unique fields.

Reallly apprecaite if anyof you could help me from this?

[AndyHunt]

A couple of things:
- that works fine here (on Solaris 8)! What OS are you on?
- I assume that you're seeing the following output:
DEFAULT
DEFAULT
MENU
is that right? If not, what output are you seeing?
(I see:
DEFAULT
MENU
)

- Also, this isn't anything to do with perl - I'm new here too, so I'm not sure how strict people are, but you may get better help in the Linux / Unix / BSD forum.

HTH

Andy

[numberwhun]

Hello! Just as a note, when you post to the forum, be sure to post the code that you have tried thus far, that way, we can help you work out any errors/issues you are experiencing.

As for your issue, I am in a code writing mood today and have whipped up something really quick.

You mentioned using a regular expression to pull out the 6th field. Sure, you could do that, but that's kind of like using a hammer to open the door by breaking the window when you have the key in your pocket.

Instead, since your fields are "|" (pipe) delimited, why not feed each line into the split function using a while loop, and pull out the 6th field (or element [5] of the array)? To me, this was much easier. Save the regex's for when you really need them, of course, don't let me stop you from trying that route as it is great to learn regex's if you haven't already.

Here is the code:

use strict;
use warnings;
 
open(FILE, "<Text1.txt");
 
while(<FILE>)
{
    chomp($_);
    my @line = split(/\|/, $_);
 
    print("$line[5]\n");
}
 

Also, your line of code:

cut -d \| -f6 <filename> | sort | uniq
 

is a line from a shell script, not Perl. Sure, you could put that inside back tics or a system() function, but if you are going to code in Perl, then do so.

Regards,

Jeff

[miller]

As has already been stated, this is not truly a perl issue. However, it can be solved fairly easily with perl.

The following code prints out only the unique values for the 6th column in the DATA file handle:

my %seen = ();
while (<DATA>) {
    chomp;
    my @columns = split '\|';
    print "$columns[5]\n" if ! $seen{$columns[5]}++;
}
 
__DATA__
000046571|1000025|CUSTOMER|27-JUN-2007 06:27:59|005|DEFAULT
000046572|1000026|ACTIVATE|16-JUL-2007 12:33:13|013|DEFAULT
000046572|1000026|ACTIVATE|16-JUL-2007 12:33:13|018|MENU
 

This technique is documented here:

perlfaq4 Data Manipulation - How can I remove duplicate elements from a list or array?

- Miller