perl script help

hi,
I am new to perl programming.I am trying with the following script and
need help for it.

I consolidated 10 excel files(in .txt format) which has same headers
in it and so i made it 1 common header at the top.While doing it,in
final output file i see a blank row at the beginning of every file
consolidated.I wanted to get rid of it and to be displayed all in a
single file.

Sample Script:

while() {
if (($k ==0) and ($Line_Counter ==1)) {
my @F=split(/[\t]+/, $_);
print CONSOL_FILE "$F[0] \t $F[1] \t $F[2] \n";
}
if (($k >=1) and ($Line_Counter>1)) { # doesnt print headers
$Line=$_;
my @F=split(/[\t]+/, $Line);
print CONSOL_FILE "$F[0] \t $F[1] \t $F[2] \n";
}
$Line_Counter = $Line_Counter + 1;
}
close FILE ;
note:tab is the delimiter used here.

Any help is Appreciated.


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RE: perl script help

> From: james varghese [mailto:james24.v@gmail.com]
> Sent: Tuesday, October 11, 2011 8:31 AM
> To: beginners@perl.org
> Subject: perl script help
>
> hi,
> I am new to perl programming.I am trying with the following script and
> need help for it.
>
> I consolidated 10 excel files(in .txt format) which has same headers
> in it and so i made it 1 common header at the top.While doing it,in
> final output file i see a blank row at the beginning of every file
> consolidated.I wanted to get rid of it and to be displayed all in a
> single file.
>
> Sample Script:
>
> while() {
> if (($k ==0) and ($Line_Counter ==1)) {
> my @F=split(/[\t]+/, $_);
> print CONSOL_FILE "$F[0] \t $F[1] \t $F[2]
\n";
> }
> if (($k >=1) and ($Line_Counter>1)) { # doesnt
> print headers
> $Line=$_;
> my @F=split(/[\t]+/, $Line);
> print CONSOL_FILE "$F[0] \t $F[1] \t $F[2]
> \n";
> }
> $Line_Counter = $Line_Counter + 1;
> }
> close FILE ;
> note:tab is the delimiter used here.
>
> Any help is Appreciated.
>

Hi,
Not certain if this is your problem, but you probably want to 'chomp' the
input after reading a line.
Also, what is $k?
You may be able to read the first line outside the loop and print the
header. Then you would not have to worry about the checks for $line_number
(and $k?).
And why do you assign $Line to $_? Seems like an unnecessary step.
As an aside, when referring to the Perl programming language it is usually
capitalized (Perl).
Ken





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Re: perl script help

On 10/11/11 Tue Oct 11, 2011 5:31 AM, "james varghese"
scribbled:

> hi,
> I am new to perl programming.I am trying with the following script and
> need help for it.
>
> I consolidated 10 excel files(in .txt format) which has same headers
> in it and so i made it 1 common header at the top.While doing it,in
> final output file i see a blank row at the beginning of every file
> consolidated.I wanted to get rid of it and to be displayed all in a
> single file.

Are you saying that there is a blank line in the consolidated file just
before the first line of each copied file? I will assume so, but please
correct me if I am wrong.

>
> Sample Script:
>
> while() {
> if (($k ==0) and ($Line_Counter ==1)) {
> my @F=split(/[\t]+/, $_);
> print CONSOL_FILE "$F[0] \t $F[1] \t $F[2] \n";
> }
> if (($k >=1) and ($Line_Counter>1)) { # doesnt print headers
> $Line=$_;
> my @F=split(/[\t]+/, $Line);
> print CONSOL_FILE "$F[0] \t $F[1] \t $F[2] \n";
> }
> $Line_Counter = $Line_Counter + 1;
> }
> close FILE ;
> note:tab is the delimiter used here.
>
> Any help is Appreciated.
>

You have not shown us the whole program, so it is difficult to help you. I
see nothing wrong with the logic of your program, so the problem may lie
with what you have not shown us.

Specifically, what is $k, what is its initial value, and when does the value
change? It looks like a file counter. Also, what is the initial value of
$Line_Counter, and does it get re-initialized for each file read?

Assuming $k is a file counter starting at zero, and $Line_Counter is a line
counter starting at one, you can use the following logic to skip printing
the first line of each file read except for the first:

if( $k == 0 or $Line_Counter > 1 ) {
print join("\t",@F);
}

If you are getting blank lines and just want to eliminate them, then test
for blank lines by putting this line in your while loop:

next if /^\s*$/;

This will skip any line consisting only of whitespace. If your definition of
blank line differs from that, please let us know what it is.

Other suggestions:

1. Put 'use strict;' and 'use warnings;' in your program.
2. Use the $. built-in variable as a line counter.
3. Use join as shown for printing.
4. Improve your indenting for readability.
5. Be more consistent in naming and using variables, as in $k and
$Line_Counter.

Good luck!



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Re: perl script help

Thanks for the Suggestions Ken Slater and Jin Gibson.

Sorry for the missing information's.

Exactly what you people predicted is correct.($k is a file counter
starting at zero, and $Line_Counter is a line counter starting at one)

Script is modified according to the suggestions given by you and now
its working fine.

Thanks again,
James



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