read column in perl

dee00zee has asked for the wisdom of the Perl Monks concerning the following question:

I have 2 files to read from, namely file1 and file2.
I want to insert the content of file1 to be the
2nd column of file2.

content of file1

a
b
c
d
e
[download]

content of file2

1    6    11
2    7    12
3    7    13
4    8    14
5    9    23
[download]

I want the output to be as follows

1    a    6    11
2    b    7    12
3    c    7    13
4    d    8    14
5    e    9    23
[download]

My code didn't return the result I want

#!/bin/perl

open(IN,"file1");
open(IN2,"file2");
open (OUT,"> output"); 

while($str=<IN2>)
{        
        @array=split(/\s+/,$str);
        
        
while($data=<IN>)
    {
        @box=split(/\s+/,$data);
        
            foreach $item(@array)
            {
    splice (@box,2,0,"$array($item)");
                print OUT "@box\n";
                
            }
            
    }
    

}
[download]

20050308 Janitored by Corion: Added code tags.

Comment on read column in perl Select or Download Code

Replies are listed 'Best First'.
Re: read column in perl by jmcnamara (Monsignor) on Mar 08, 2005 at 09:09 UTC
Here is a one-liner for a Unix system: `$ paste file1 file2 \| perl -lane 'print "@F[1,0,2,3]"' 1 a 6 11 2 b 7 12 3 c 7 13 4 d 8 14 5 e 9 23` [download] Or this: `$ paste file1 file2 \| awk '{print $2, $1, $3, $4}'` [download] You can change the field separator in either example to suit. -- John.	[reply] [d/l] [select]
Re^2: read column in perl by DentArthurDent (Monk) on Mar 08, 2005 at 12:54 UTC
I wish I could ++ that 5 times. It showed me a new UNIX command, and the perl arguements at the same time. Great work! ---- My mission: To boldy split infinitives that have never been split before!	[reply]
Re^3: read column in perl by jmcnamara (Monsignor) on Mar 08, 2005 at 13:29 UTC
I like to remind people that Unix isn't there just to bootstrap perl. `;-)` -- John.	[reply]
Re^4: read column in perl by wolfger (Deacon) on Mar 08, 2005 at 13:41 UTC
Re: read column in perl by ikegami (Patriarch) on Mar 08, 2005 at 07:20 UTC
Only one loop is needed. `#!/bin/perl open(IN, "file1"); open(IN2, "file2"); open(OUT, "> output"); while ($str = <IN>) { chomp($str); $data = <IN2>; chomp($data); @box = split(/\s+/, $data); splice(@box, 1, 0, $str); print OUT (join(' ', @box) . "\n"); }` [download]	[reply] [d/l]
Re: read column in perl by jbrugger (Parson) on Mar 08, 2005 at 07:20 UTC
Hi dee00zee, I see you've written a few nodes now, and i wonder why you're not using <code> tags. Since you're not totally new here, i assume you have read Perl Monks Approved HTML tags and Writeup Formatting Tips? `#!/bin/perl use strict; open(IN,"file1"); open(IN2,"file2"); open (OUT,"> output"); while (my $str = <IN>) { chomp($str); my $data = <IN2>; $data =~ s/(.?)\s(.)/$1 $str $2/; print OUT ($data); }` [download]	[reply] [d/l]
Re: read column in perl by sh1tn (Priest) on Mar 08, 2005 at 08:02 UTC
`use strict; open IN1, "file1" or die $!; open IN2, "file2" or die $!; open OUT, ">output"or die $!; my @file1; my @file2; chomp, push @file1, $_ while <IN1>; chomp, push @file2, $_ while <IN2>; close IN1; close IN2; my $i = 0;$file1[$i] .= "\t".(join "\t", split '\s', $_), $i++ for @fi +le2 ; print "$_$/" for @file1; print OUT "$_\n" for @file1; __END__ a 1 6 11 b 2 7 12 c 3 7 13 d 4 8 14 e 5 9 23` [download]	[reply] [d/l]
Re^2: read column in perl by dragonchild (Archbishop) on Mar 08, 2005 at 13:39 UTC
You don't want to read the whole file in if you don't have to - that doesn't scale well to files that are larger than your physical RAM. (Swap space is so slooooow!) Furthermore, the following can be rewritten: `my @file1; my @file2; chomp, push @file1, $_ while <IN1>; chomp, push @file2, $_ while <IN2>; ############## chomp(my @file1 = <IN1>); chomp(my @file2 = <IN2>);` [download] Being right, does not endow the right to be rude; politeness costs nothing. Being unknowing, is not the same as being stupid. Expressing a contrary opinion, whether to the individual or the group, is more often a sign of deeper thought than of cantankerous belligerence. Do not mistake your goals as the only goals; your opinion as the only opinion; your confidence as correctness. Saying you know better is not the same as explaining you know better.	[reply] [d/l]