A simple variable count inside array

Question

After working with this code, I am stuck at what I think is a simple error, yet I need outside eyes to see what is wrong.

I used unpack function to divide an array into the following.

@extract = 

------MMMMMMMMMMMMMMMMMMMMMMMMMM-M-MMMMMMMM  
------SSSSSSSSSSSSSSSSSSSSSSSSSS-S-SSSSSDTA
------TIIIIIIIIIIIIITIIIVVIIIIII-I-IIIIITTT

Apparently, after unpacking into the array, when I try to go into the while loop, @extract shows up completely empty. Any idea as to why this is happening? print @extract; #<-----------Prints input

my $sum = 0;
my %counter = ();
while (my $column = @extract) {
print @extract; #<------- This extract is completely empty. Should be input

for (my $aa = (split ('', $column))){
    $counter{$aa}++;
    delete $counter{'-'}; # Don't count -
    }

    # Sort keys by count descending  

    my @keys = (sort {$counter{$b} <=> $counter{$a}} keys %counter) [0]; #gives highest letter
    for my $key (@keys) {
        $sum += $counter{$key};
        print OUTPUT "$key   $counter{$key}   ";

start by writing code that gets the highest count for a single line; then wrap a loop over your lines around that; you seem to be confusing the two tasks here. — ysth
– ysth, Commented Apr 13, 2014 at 23:32
You are right ysth, got to add another loop element so as to count the individuals. Thank you — Gyler
– Gyler, Commented Apr 14, 2014 at 0:19

Gabs00 · Accepted Answer · 2014-04-14 00:26:02Z

1

Each line is an array element correct? I don't see in your code where you are checking the individual characters.

Assuming the input that you have shown is a 3 element array containing the line as a string:

#!/usr/bin/perl

use strict;
use warnings;

my @entries;

while(my $line = shift(@extract)){
    my %hash;
    for my $char(split('', $line)){
        if($char =~ /[a-zA-Z]/) { $hash{$char}++ }
    }

    my $high;
    for my $key (keys %hash) { 
        if(!defined($high)){ $high = $key }
        elsif($hash{$high} < $hash{$key}){ 
            $high = $key
        }
    }

    push @entries, {$high => $hash{$high}};
}

Note this empties @extract, if you don't want to do that you'd have to use a for loop like below

for my $i (0 .. $#extract){
    #my %hash etc...
}

EDIT: Changed it so that only the highest number is actually kept

edited Apr 14, 2014 at 0:26

answered Apr 14, 2014 at 0:10

Gabs00

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6 Comments

Gyler Over a year ago

Thanks Gabs00, will give this a try ASAP. Appreciate the time and effort.

TLP Over a year ago

You don't have to use array indexes with for, you can just use for my $line (@extract).

Gabs00 Over a year ago

@TLP, that is correct, for me its a form of habit since I usually need to know the index.

Gyler Over a year ago

@Gabs00 Your post is logical, I tried to run it with my given input but it is not getting any results. Will keep you updated.

Gabs00 Over a year ago

@Gyler does it give any results?

|

Chris Charley · Accepted Answer · 2014-04-14 02:40:20Z

0

An approach using reduce from List::Util.

#!/usr/bin/perl
use strict;
use warnings;
use List::Util 'reduce';

my @extract = qw/
------MMMMMMMMMMMMMMMMMMMMMMMMMM-M-MMMMMMMM
------SSSSSSSSSSSSSSSSSSSSSSSSSS-S-SSSSSDTA
------TIIIIIIIIIIIIITIIIVVIIIIII-I-IIIIITTT
/;


for (@extract) {
    my %count;
    tr/a-zA-Z//cd;
    for (split //) {
        $count{$_}++;   
    }
    my $max = reduce { $count{$a} > $count{$b} ? $a : $b } keys %count;
    print "$max $count{$max}\n";
}

answered Apr 14, 2014 at 2:40

Chris Charley

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