Re: extracting single column

#!/bin/perl -w
use strict;
#for a csv file you can try something like this,
#but there are dozens of ways to do this.
#you should read a book called "Sam's learn perl in
#24 hours" (or similar title).

#variables you can change to suit your needs
my $column_separator = ",";
my $column_number = "3";
$column_number--;
my $file="filename.ext";
open(FILE,"<","$file");
my @lines=<FILE>;
close FILE;

foreach my $line (@lines){
 my @columns = split(/$column_separator/,"$line");
 print $columns[$column_number],"\n";
}
[download]

Comment on Re: extracting single column Download Code

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Re^2: extracting single column by Sewi (Friar) on Feb 10, 2012 at 09:47 UTC
There are few lines where I don't agree: `my $column_separator = ",";` [download] Better: `my $column_separator = qr/,/;` [download] ...imaging someone wants to use "." as separator. `my $column_number = "3";` [download] Don't write numbers as text, write them as numbers (cut away those " chars). Loading the whole file into memory might not be that good idea, imagine it's a 10 GB file. Why not parse it line-by-line? `open(FILE,"<","$file"); while (<FILE>) { my @columns = split(/$column_separator/); print $columns[$column_number],"\n"; } close FILE;` [download] Try out Padre - the free Perl IDE and visit my blog's Perl section.	[reply] [d/l] [select]
Re^2: extracting single column by Anonymous Monk on Jun 04, 2013 at 04:19 UTC
Hey my column has around 900 entries , this code does not extract all of them , but only a part of them . so if you can modify this for me , I will be grateful	[reply]