Troubles appending arrays

[Perlwannabe]

Hello,

I made a simple script that picks up words from a text file A and save them in text file B each time I call the script.
I would that it appends the new array just under the existing one but the first word stands on the side:

Array:

bla
bla
bla
bla

After I add a new array should be:

bla
bla
bla
bla
bla
bla
bla
bla

Instead is:

bla
bla
bla
blabla (the last and the first coincide)
bla
bla
bla

Why this? What can I do?
Here is the very short script (didaptic):

#!perl

# reading data from file A

# open file A to read
open(A,"filea.txt")||die("could not open file!");

# store them in an array
@a=<A>;

# close
close(A);

# writing data on file B

# open file B to write (append)
open(B,">>fileb.txt")||die("could not open file!");

# print data
print A;

# close
close(B);

# open file B to print a check
open(B,"fileb.txt")||die("error");
@b=<B>;
close(B);

# print results as html
print "Content-type: text/html\n\n";
foreach $line(@b)
{
print $line;print"<br>\n";
}
exit;

Thanks for a kind help

Sincerely

 

[Perlwannabe]

Excuse me:

I made a mistake writing the function under this comment:

# print data

It is:

# print data
print B(@a);

Thanks!

 

[MillerH]

Note 1: "print B(@a)" should be "print B (@a);" with a space, otherwise an undefined function error will be thrown.

All that is your problem is that the final line of your filea.txt data file does not contain a return character. You can edit the data file yourself and add such a character, or you can add the following code to protect against that condition.

# close
close(A);

# Fix final return character.
chomp($a[-1]); $a[-1] .= "\n";

 

[MillerH]

And as a minor tidbit, you could clean up your code with some use of the File::Slurp module.

#!perl

use File::Slurp qw(read_file append_file);

# reading data from file A
my $data = read_file('filea.txt');
chomp($data); $data .= "\n";

# writing data on file B (append)
append_file('fileb.txt', $data);

# open file B to print a check
my @b = read_file('fileb.txt');

# print results as html
print "Content-type: text/html\n\n";
foreach $line(@b)
{
print $line . "<br>\n";
}
exit;

 

[Perlwannabe]

Thanks very much MillerH!

I checked your code to fix the final return character
but now it "skips" the appending:

bla
bla
bla
bla

after the appending:

bla
bla
bla

bla
bla
bla

Seems like if it deletes last and first array elements...

 

[MillerH]

It works fine on my end. In order to help you debug whatever you're doing wrong, I'll need to see your current code. It would also be a good idea if you would attach your data filea.txt. Or is it still just "bla\n" x 4?

 

[Perlwannabe]

Very grateful for your support.

Here is my current code:

#!perl

# reading data from file A

# open file A to read
open(A,"filea.txt")||die("could not open file!");

# store them in an array
@a=<A>;

# close
close(A);

# prepare to append
$a[-1] = "\n";
chomp($a[-1]);

# writing data on file B

# open file B to write (append)
open(B,">>fileb.txt")||die("could not open file!");

# print data
print B (@a);

# close
close(B);

# open file B to print a check
open(B,"fileb.txt")||die("error");
@b=<B>;
close(B);

# print results as html
print "Content-type: text/html\n\n";
foreach $line(@b)
{
print $line;print"<br>\n";
}
exit;

I just inverted $a and chomp function but now it seems to "eat" the last array element...

As regard my filea.txt it is just "bla"x4, nothing complex.

Thanks again

 

[MillerH]

As I thought, you did not paste my code in correctly. Look again at what I gave you and paste it correctly. Instead of chomping an optinal return character and then forcing the additional of one, you are setting the last element to a return character and then chomping it. Along with the wrong order, you removed the concatenation operator.

If you really want it in two lines then just use this:

# Fix final line's return character
chomp($a[-1]);
$a[-1] .= "\n";

 

[Perlwannabe]

OK!!!
It works fine!

yes, I missed the "." operator in pasting...

Thank you!

I see you the next