Chomp is removing the whole word instead of the newline

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

Hi,

I am facing issues with perl chomp function. I have a test.csv as below:

col1,col2
vm1,fd1
vm2,fd2
vm3,fd3
vm4,fd4
[download]

I want to print the 2nd field of this csv. This is my code:

#!/usr/bin/perl -w
use strict;

my $file = "test.csv";
open (my $FH, '<', $file);
my @array = (<$FH>);
close $FH;

foreach (@array)
{
    my @row = split (/,/,$_);
    my $var = chomp ($row[1]);     ###   <<< this is the problem
    print $var;
}
[download]

The output of aboe code is :

11111
[download]

I really don't know what is "11111". Actually, the last field can be printed as below:

foreach (@array)
{
    my @row = split (/,/,$_);
    print $row[1];     ###  << Note that I am not printing "\n"
}
[download]

the output is:

vm_cluster
fd1
fd2
fd3
fd4
[download]

Now, i am using these field values as an input to the DB and the DB INSERT statement is failing due this invisible newline. So I thought chomp would help me here. instead of chomping, it gives me "11111".

I also tried below loop:

foreach (@array)
{
    my @row = split (/,/,$_);
    chomp ($row[1]); 
    my $var = $row[1]; 
    print $var;
}
[download]

But above loop will not print anything (not even the "11111" output mentioned above). Meaning, chomp is removing the last string and the trailing new line.

Could you help me understand what am i doing wrong here.

Also please find my discussion on stackoverflow for this issue: http://stackoverflow.com/questions/11645696/perls-chomp-chomp-is-removing-the-whole-word-instead-of-the-newline

Thanks.

Comment on Chomp is removing the whole word instead of the newline Select or Download Code

Replies are listed 'Best First'.
Re: Chomp is removing the whole word instead of the newline by Ratazong (Monsignor) on Jul 25, 2012 at 09:34 UTC
From the docs: It (chomp) returns the total number of characters removed from all its arguments So `my $var = chomp ($row[1]);` is not doing what you expect it to do. Rata	[reply] [d/l]
Re^2: Chomp is removing the whole word instead of the newline by slayedbylucifer (Scribe) on Jul 25, 2012 at 09:51 UTC
You know what, i did read exact same line in the documentation but I think i did not interpret it correctly. thanks for your time.	[reply]
Re: Chomp is removing the whole word instead of the newline by tobyink (Canon) on Jul 25, 2012 at 09:35 UTC
`chomp` operates in-place. The return value isn't especially useful. `use 5.010; say "enter some text lines"; while (my $line = <>) { say "\$line is [[$line]]"; say "doing the chomp thing!"; my $return = chomp $line; say "\$line is now [[$line]]"; say "\$return is [[$return]]"; }` [download] `perl -E'sub Monkey::do{say$_,for@_,do{($monkey=[caller(0)]->[3])=~s{::}{ }and$monkey}}"Monkey say"->Monkey::do'`	[reply] [d/l] [select]
Re^2: Chomp is removing the whole word instead of the newline by slayedbylucifer (Scribe) on Jul 25, 2012 at 09:52 UTC
Correct, As Ratazong said above, I could not interpret this information correctly. Thnaks for your time.	[reply]
Re: Chomp is removing the whole word instead of the newline by choroba (Cardinal) on Jul 25, 2012 at 09:38 UTC
Your last example works for me, that's how chomp should be used. The output: `col2fd1fd2fd3fd4` [download] Notice there is no newline at the end. The output might be buffered, i.e. it will not be shown before you print a newline or finish the script.	[reply] [d/l]
Re^2: Chomp is removing the whole word instead of the newline by slayedbylucifer (Scribe) on Jul 25, 2012 at 09:55 UTC
exactly. On my fedora, It does show output. But on my ubuntu, it does not show any output unless I add "\n" to the print statement. Is this an expected behaviour ?	[reply]
Re^3: Chomp is removing the whole word instead of the newline by Anonymous Monk on Jul 25, 2012 at 10:15 UTC
Tutorials: Input and Output: Suffering from Buffering?	[reply]
Re: Chomp is removing the whole word instead of the newline by thonar (Monk) on Jul 25, 2012 at 13:03 UTC
`... my @row = split (/,/,$_); # I believe this is what you trying to do chomp( my $var = $row[1]); # Or maybe a little bit more understandable $var = $row[1]; chomp $var; # Return the total number of characters removed in $row[1] to $chomp_r +esult # (in your case every 1 stands for a character chomp found in $row[1] +could # be a line break or something like that ) my $chomp_result = chomp( $row[1]); print "$var \|\| $chomp_result\n"; ...` [download] I hope you get what i'm trying to say ...	[reply] [d/l]
Re^2: Chomp is removing the whole word instead of the newline by slayedbylucifer (Scribe) on Jul 26, 2012 at 03:49 UTC
So, I was quite frustrated with this easy looking task bugging me for the whole day long. I really appreciate everyone who responded. Finaly I ended up using Text::CSV perl module and then calling each of the CSV field as array reference. There was no need left to run the chomp after using Text::CSV. Here is the code: `#!/usr/bin/perl use warnings; use strict; use Text::CSV; my $csv = Text::CSV->new ( { binary => 1 } ) # should set binary attr +ibute. or die "Cannot use CSV: ".Text::CSV->error_diag (); open my $fh, "<:encoding(utf8)", "vm.csv" or die "vm.csv: $!"; <$fh>; ## this is to remove the column headers. while ( my $row = $csv->getline ($fh) ) { print $row->[1]; }` [download] and here is hte output: `fd1fd2fd3fd4` [download] Later i was pulled these individual values and inserted into the DB. Thanks everyone.	[reply] [d/l] [select]
Re^2: Chomp is removing the whole word instead of the newline by slayedbylucifer (Scribe) on Jul 26, 2012 at 03:47 UTC
Agree. Thanks for your time.	[reply]
Re: Chomp is removing the whole word instead of the newline by Anonymous Monk on Jul 25, 2012 at 09:41 UTC
I am facing issues with perl chomp function ... Could you help me understand what am i doing wrong here. Well, for some reason, you're not copying the example from the chomp documentation	[reply]

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