Re^3: Copying files from one file to another file

[AnomalousMonk]

Try something like:

c:\@Work\Perl\monks>perl -wMstrict -MData::Dump -le
"my @lines = (
   'foo: 12 : //comment twelve ',
   'bar: 13 : //comment thirteen',
   'foo:  5  : //comment five',
   );
 ;;
 my %hash;
 for my $line (@lines) {
   my ($k, $v) = split qr{ : \s+ }xms, $line, 2;
   push @{ $hash{$k} }, $v;
   }
 dd \%hash;
"
{
  bar => ["13 : //comment thirteen"],
  foo => ["12 : //comment twelve ", "5  : //comment five"],
}

push-ing to an  @{ ... } array referenced by a hash key  $hash{$k} autovivifies an array reference if it did not already exist. See "autovivification" in perlglossary and here.

[harishnv]

I didn't understand from here, Dd\%hash; And next line meaning? Can I know more about it?

[karlgoethebier]

"...I didn't understand from here..."

I guess it's just because some of the elder fellow monks are a lazy bunch.

Consider this untested snippet or sketch - as you like:

#!/usr/bin/env perl

use strict;
use warnings;
use Data::Dump;
use feature qw (say);

my %HoA = (
    bar => ["13 : //comment thirteen"],
    foo => [ "12 : //comment twelve ", "5  : //comment five" ],
);

dd \%HoA;

say qq(\n--\n);

# like in "Perl Programming" AKA "Camel Book" chapter 9...
for my $key ( keys %HoA ) {
    say qq($key: );
    for my $item ( 0 .. $#{ $HoA{$key} } ) {
        say qq( $item = $HoA{$key}[$item]);
    }
    print qq(\n);
}

__END__

Best regards, Karl

[AnomalousMonk]

... some of the elder fellow monks are a lazy bunch.

Elderly, very lazy, and growing grouchier by the minute :)

[harishnv]

the keyword "say" isn't working for me

[harishnv]

the path is written in terminal/ command window right? " code " should I put those apostrophe? Data::Dump::dd() is enough in the first line of the code?

[AnomalousMonk]

the path is written in terminal/ command window right?

Yes.

" code " should I put those apostrophe?

No. The double-quotes (not apostrophes) are only needed on the command line for specifying source code for the  -e command-line switch. See perlrun. The command-line format is only my personal way of presenting example code. What is found inside the " code " double-quotes (but not the double-quotes themselves!) is the source code you can put into a regular Perl  .pl source code file to be run from the command line in the usual way (assuming Windows):
    c:\yourprompt>perl your-source-code-file.pl


Data::Dump::dd() is enough in the first line of the code?

This is what I would put on the first few lines of my source file:

use warnings;  # always
use strict;    # always

use Data::Dump qw(dd);  # if you want to use dd()

...  # the rest of your source code

[harishnv]

Can you write comments for the code? Didn't understand dd \%hash; from there

[shmem]

dd() is a function exported by Data::Dump. Since %hash as argument to dd would be expanded into a flat list, a reference to %hash is passed to dd. That's what the backslash does, it is the reference operator. See perlref.

The next lines are sample output produced by dd.

[AnomalousMonk]

dd \%hash;

This statement "dumps" data from a data structure. The data structure must be passed to  dd as a reference, hence  \%hash takes a reference to the hash. See Data::Dump::dd(). (Note: There are many data dumpers. I like Data::Dump, but it's not core. The Data::Dumper module comes as a part of the core Perl "standard" installation.)

{
  bar => ["13 : //comment thirteen"],
  foo => ["12 : //comment twelve ", "5  : //comment five"],
}

This is the output of the  dd \%hash; statement. It appears immediately after the
    c:\@Work\Perl\monks>perl -wMstrict -MData::Dump -le " ... "
command line invocation used to execute the example code.

[harishnv]

any other solution? this is not working for me please, help me.

[harishnv]

Can someone help me out asap.

[harishnv]

not able to get the output

[hippo]

Short, Self-Contained, Correct Example required (again).

[harishnv]

I have commented below with problem and code. please check and help me.