reading text file and writing to two dimensional array in perl? [closed] - perl

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#!/usr/bin/perl
use strict;
use warnings;
use utf8;
use open ':encoding(UTF-8)', ':std';
use List::Util qw( sum );
my $filename = 'data1.txt';
open(my $fh, '<:encoding(UTF-8)', $filename)
or die "Could not open file '$filename' $!";
while (my $row = <$fh>) {
chomp $row;
print "$row\n";
}
my $filename2 = 'data2.txt';
open(my $fh2, '<:encoding(UTF-8)', $filename2)
or die "Could not open file '$filename2' $!";
while (my $row = <$fh2>) {
chomp $row;
print "$row\n";
}
my #last = ();
my %grades = (
Ahmet => {
quiz1 => 97,
quiz2 => 67,
quiz3 => 93,
},
Su => {
quiz1 => 88,
quiz2 => 82,
quiz3 => 99,
});
my %sum;
for my $name (keys %grades){
$sum{$name} = sum(values %{ $grades{$name} });
}
for my $name (sort { $sum{$a} <=> $sum{$b} } keys %sum){
push #last, "$name: $sum{$name}\n";
}
my %grades2 = (
Bugra => {
quiz1 => 33,
quiz2 => 41,
quiz3 => 59,
},
Lale => {
quiz1 => 79,
quiz2 => 31,
quiz3 => 62,
},
);
my %sum2;
for my $name (keys %grades2){
$sum2{$name} = sum(values %{ $grades2{$name} });
}
for my $name (sort { $sum2{$a} <=> $sum2{$b} } keys %sum2){
push #last, "$name: $sum2{$name}\n";
}
my #last1 = sort { lc($a) cmp lc($b) } #last;
print #last1;
This is my code. I want to take values from a text file something like ( marry 10 65 23) and write to a two dimensional array. I managed array separately end of the read text file it has to be seen like grade1 and grade2 for data1.txt and data2.txt. I can pull the values but I couldn't write to two dimensional array. Also result is correct.

Answer 1

I read your question as How do I populate the hashes %grade1 and %grade2 from the files data1.txt and data2.txt?
I also assume that your files data1.txt and data2.txt have the following structure (whitespace separated):
marry 10 65 23
john 20 30 40
I suggest to write a function that takes the filename as paramater and returns a reference to a populated hash:
sub read_grades_from_file
{
my $filename = shift;
my $result = {};
open( my $fh, '<:encoding(UTF-8)', $filename )
or die "Could not open file '$filename' $!\n";
while ( my $row = <$fh> ) {
next unless $row =~ /\S/; # skip empty lines
my ( $name, $quiz1, $quiz2, $quiz3 ) = split( ' ', $row );
$result->{$name} = {
quiz1 => $quiz1,
quiz2 => $quiz2,
quiz3 => $quiz3,
};
}
close($fh);
return $result;
}
The function is used as follows:
my $result = read_grades_from_file('data1.txt'); # returns hashref
my %grade1 = %{$result}; # dereference $result to make it a hash
$result = read_grades_from_file('data2.txt');
my %grade2 = %{$result};
The result of read_grades_from_file is a reference to a hash so it has to be de-referenced and then assigned to %grade. Thus the two steps.

Answer 2

Perhaps the data structures you are using are overly complex. You probably only need a single %grades hash, for example.
The following will take data from space- or tab-separated records from both two input files - ignoring comments or empty lines.
my %grades;
while (1) {
my $row1 = <$data1>;
my $row2 = <$data2>;
last unless (defined $row1 or defined $row2);
chomp ($row1, $row2);
if (defined $row1 and $row1 !~ /(^#|^$)/) {
my ($name, #quizzes) = split /[ \t]/, $row1, 4;
$grades{$name}{'grades1'} = sum(#quizzes);
}
if (defined $row2 and $row1 !~ /(^#|^$)/) {
my ($name, #quizzes) = split /[ \t]/, $row2, 4;
$grades{$name}{'grades2'} = sum(#quizzes);
}
}
To print to STDOUT, you could try the following.
print "Name\tMarks 1\tMarks 2", $/;
for (keys %grades) {
my $name = $grades{$_};
print $_, "\t", $name->{grades1} || '?', "\t", $name->{grades2} || '?', "\t", $/;
}
With data1.txt as
# Grades
Bugra 33 41 59
Mary 10 65 23
Lale 79 31 62
and data2.txt as
# Grades 2
Bugra 49 32 57
Lale 79 31 62
Peter 21 34 42
the output is shown below.
Name Marks 1 Marks 2
Peter ? 97
Lale 172 172
Bugra 133 138
Mary 98 ?
(A '?' indicates that no record exists for the specified student in one of the two input files.)