in reply to Regexp and reading a file n-lines at time

This would work, You'll get hash of arrays

#!/usr/bin/perl
use strict;
use warnings;
use Data::Dumper;

my $HASH;
my $Title;
while ( <DATA> ) {
    chomp;
    next if ! $_;
    if ( /^\d+\.(.*)/sg ) {
        $Title = $1;        
        $HASH->{$Title} = [];
        next;
    }
    if ( exists $HASH->{$Title} ) {
        push @{$HASH->{$Title}} , $_;
    }

}

print Dumper($HASH);

__DATA__
1.TITLE OF FIRST RECIPE

abstract

Recipe 1.
Recipe 2.
Recipe ...

Procedure...


2.TITLE OF SECOND RECIPE
...

[download]

Replies are listed 'Best First'.
Re^2: Regexp and reading a file n-lines at time
by jwkrahn (Abbot) on Feb 01, 2010 at 15:42 UTC 
        if ( /^\d+\.(.*)/sg ) {

    [download]

    Your pattern is anchored at the beginning of the string so the /g option is superfluous.    The string in $_ contains only one line so the use of the /s option is also superfluous.

[reply]
[d/l]
[select]
Re^2: Regexp and reading a file n-lines at time
by epimenidecretese (Acolyte) on Feb 01, 2010 at 13:32 UTC

    Yes,ahmad's solution works perfectly.

    Now,I just have to understand it completely and tag the output.

    Could you give me a hint where to look for(in the documentation) to understand the code inside the while block ?

    Thank you very much.

[reply]
[d/l]
Re^2: Regexp and reading a file n-lines at time
by epimenidecretese (Acolyte) on Feb 03, 2010 at 10:13 UTC

    I got interesting results with hash of arrays,but I don't know how to access the single titles and then each element of the arrays into them.

    I think I'm working with anonymous hashes and arrays,right ? In this case,how do I access to an anonymous hash ?

     $HASH->{$Title} = []; This is just here to initialize an empty array ?

    I'm looking for something like: 

    my $abstract=shift @{$HASH->{$Title}->{???}}#here I need to access eac
+h single title in order to get the first element of each (anonymous) 
+hash
print "<abstract>"."$abstract"."</abstract>\n";

#here I should print all the element between the first  and the last o
+ne of the array in each single hash

my $procedure=pop @{$HASH->{$Title}}#same as before
print "<procedure>"."$procedure"."</procedure>\n";

    [download]

    One of Crete's own prophets has said it: 'Cretans are always liars, evil brutes, lazy gluttons'.
    He has surely told the truth.

[reply]
[d/l]
[select]

      I finally got it!

      Here is my solution and it works perfectly: 

      foreach $Title (keys %{$HASH}) {

print $OUT "<recipe>".$Title."</recipe>\n";

my $abstract=shift @{$HASH->{$Title}};

print $OUT "<abstract>".$abstract."</abstract>\n";

my $procedure=pop @{$HASH->{$Title}};

foreach my $ingredient (@{$HASH->{$Title}}) {

    print $OUT "<ingredient>".$recipe."</ingredient>\n";
}
print $OUT "<procedure>".$procedure."</procedure>\n";
}

      [download]

      Read more... See data... (3 kB)

      Thank you very much,guys!I think I'm going to love this place.

      One of Crete's own prophets has said it: 'Cretans are always liars, evil brutes, lazy gluttons'.
      He has surely told the truth.

[reply]
[d/l]
[select]

        You may want to group your print statements; and you don't need to concatenate strings and variables (like "<title>".$Title."</title>") - you can print them together in one double-quoted string ("<title>$Title</title>").

        Consider: 

        foreach $Title (keys %{$HASH}) {
   my $abstract  = shift @{$HASH->{$Title}};
   my $procedure = pop @{$HASH->{$Title}};
   print $OUT "<title>$Title</title>\n",
              "<abstract>$abstract</abstract>\n",
              (map { "<recipe>$_</recipe>\n" }@{$HASH->{$Title}}),
              "<procedure>$procedure</procedure>\n";
}

        [download]
[reply]
[d/l]

In Section Seekers of Perl Wisdom