in reply to RESOLVED - parse a file TXT similar to XML

Hello x-lours,

it is not so clear to me: perhaps you should post an example of the intended final datructure, but..

if you are trying to understand the .. part, in this case it is named flip-flop operator described among Range-Operators in the perlop

To help you understand it run the following code

use strict; use warnings; my $part = 0; while (<DATA>){ chomp $_; if ( $_ =~ /objet => debut$/ .. /objet => fin$/){ print "TRUE\n"; if ( /objet => debut$/ ){ next; # we skip the opening tag } elsif ( /objet => fin$/ ){ $part++; # we increment our index $part on closing tag } else{ print "\tPART $part: [$_]\n"; # here is the meat: do what +you need } } else{ print "FALSE for line: [$_]\n"; } } __DATA__ objet => debut index => 1 a => "premiere valeur" z => "dernier mot" objet => fin ALIEN LINE AFTER fin objet => debut index => 77 a => "autre valeur" z => "aurai-je le dernier mot ?" objet => fin

..and you will see how it works:

TRUE TRUE PART 0: [index => 1] TRUE PART 0: [a => "premiere valeur"] TRUE PART 0: [z => "dernier mot"] TRUE FALSE for line: [ALIEN LINE AFTER fin] TRUE TRUE PART 1: [index => 77] TRUE PART 1: [a => "autre valeur"] TRUE PART 1: [z => "aurai-je le dernier mot ?"] TRUE

L*

There are no rules, there are no thumbs..
Reinvent the wheel, then learn The Wheel; may be one day you reinvent one of THE WHEELS.

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Re^2: parse a file TXT similar to XML -- flip-flop operator
by x-lours (Sexton) on Mar 30, 2022 at 09:38 UTC

    thank you for the reply.

    i think that learning "flip flop" (knew knowledge for me) will help me to give a Perl answer to my colleague ;-)

    the final array is sort of

    [{index=>1, a => 'premiere valeur' ... , z => 'dernier mot'}, ..., {index=>77, a => 'autre valeur' ... , z => 'aurais-je le dernier mot'}]
      Hello again,

      you can easily modify the above code to have something like:

      use strict; use warnings; use Data::Dumper; my @AoH ; my $current_hash = {}; while (<DATA>){ chomp $_; if ( $_ =~ /objet => debut$/ .. /objet => fin$/){ if ( /objet => debut$/ ){ next; } elsif ( /objet => fin$/ ){ push @AoH, $current_hash; $current_hash = {}; } else{ my ($key,$value) = split /\s+=>\s+/,$_; $current_hash->{ $key } = $value; } } else{ print "unxpected content outside tags in line: [$_]\n"; } } print Dumper \@AoH; __DATA__ objet => debut index => 1 a => "premiere valeur" z => "dernier mot" objet => fin ALIEN LINE AFTER fin objet => debut index => 77 a => "autre valeur" z => "aurai-je le dernier mot ?" objet => fin

      The above code use $current_hash as temporary container for key values pairs and need to be reset when fin is encountered. It outputs:

      unxpected content outside tags in line: [ALIEN LINE AFTER fin] $VAR1 = [ { 'a' => '"premiere valeur"', 'index' => '1', 'z' => '"dernier mot"' }, { 'z' => '"aurai-je le dernier mot ?"', 'a' => '"autre valeur"', 'index' => '77' } ];

      L*

      There are no rules, there are no thumbs..
      Reinvent the wheel, then learn The Wheel; may be one day you reinvent one of THE WHEELS.

        Thanks for the explanations

        very helpful to understand the flip-flop tool

      You may find Flipin good, or a total flop? helpful. The flip flop operator family is home to dragons.

      Optimising for fewest key strokes only makes sense transmitting to Pluto or beyond
      If the output is an Array Of Hash, I don't see the need for the flip-flop operator, as cool as that thing is. Taking your DATA verbatim and assuming that 3 dots is the record separator, the code appears to me to be straightforward. This is not "one line", but at least for me, the code is very easy to understand. Please enlighten me if the Ruby complicated thing does something that this does not?

      use strict; use warnings; use Data::Dumper; my @structure; my %temp; while (<DATA>) { next unless /\S/; # skip blank lines if (/^\.\.\./) # 3 dots ends a record { push (@structure, {%temp}); %temp=(); } else { chomp; my ($key, $value) = split /\s+=>\s+/,$_; $temp{$key}=$value; } } push (@structure, {%temp}) if (%temp); # possible last record print Dumper \@structure; =Output $VAR1 = [ { 'a' => '"premiere valeur"', 'objet' => 'debut1', 'index' => '1' }, { 'objet' => 'fin', 'z' => '"dernier mot"' }, { 'objet' => 'debut2', 'index' => '77', 'a' => '"autre valeur"' }, { 'z' => '"aurai-je le dernier mot ?"', 'objet' => 'fin' } ]; =cut __DATA__ objet => debut1 index => 1 a => "premiere valeur" ... z => "dernier mot" objet => fin ... objet => debut2 index => 77 a => "autre valeur" ... z => "aurai-je le dernier mot ?" objet => fin
      UPDATE: I looked at this thing again and I think I see a possible interpretation error of your DATA on my part. I work with some XML formats and this idea of using a specific key to indicate the start or the end of the record is my opinion, ill advised. Usually XML keys usually are not guaranteed to come in a specific order. However usually there will be clear "end of record" indication. In some files I parse, that is "\n". Here I assumed just a blank line, or end of file.

      so here is updated code:

      use strict; use warnings; use Data::Dumper; my @structure; my %temp; while (<DATA>) { if (!/\S/) # blank line ends a record { push (@structure, {%temp}) if (%temp); # possible null record %temp=(); } else { chomp; my ($key, $value) = split /\s+=>\s+/,$_; $value =~ tr/"//d; # remove double quotes $temp{$key}=$value; } } push (@structure, {%temp}) if (%temp); # possible last record print Dumper \@structure; =Output $VAR1 = [ { 'a' => 'premiere valeur', 'b' => 'some value', 'index' => '1', 'z' => 'dernier mot', 'objet' => 'fin' }, { 'a' => 'autre valeur', 'index' => '77', 'objet' => 'fin', 'z' => 'aurai-je le dernier mot ?' } ]; =cut __DATA__ objet => debut index => 1 a => "premiere valeur" b => "some value" z => "dernier mot" objet => fin objet => debut index => 77 a => "autre valeur" z => "aurai-je le dernier mot ?" objet => fin

        your updated code is what i need.

        Thank you