perlynewby has asked for the wisdom of the Perl Monks concerning the following question:

This code pretends to build a layer progression as per user input but I cannot think of a way to get the last layer into the print out

Simple task (so I thought!)- building a hierarchical progression of layers. Say the user wants to build a metal stack from M1 to M5, ie: M1->v1->M2->v2->M3->v3->M4->v4->M5.

I cannot figure out how to add the last metal (M5) into my logic, any ideas on this?

In fact, I want to add some dimensions to these metals and make sure the via is laid out within those dimensions. IS there a Perl library that I can use for that?? but that's for a later day after I complete the last array member

Anyways, this is what I have so far.

#!/usr/bin/perl

use 5.14.2;
use strict;
use warnings;
use Data::Dumper;
use diagnostics;

sub metal_stack_order {
    my @unsorted =@_ ;
    
    #make sure to arrange to ascending order
    my @sorted = sort { $a <=>$b} @unsorted;
    my ($Start,$End)=($sorted[0],$sorted[1]);
    
    for (my $i=$Start; $i <= ($End-1) ; $i++){        
        print "M$i --> V$i-->";
    }
    
        
}

say "Enter Lowest metal layer like =>  \"m1\"\n";
my $input1=<>;
say " Enter Highest metal like =>  \"m5 \"\n";
my $input2=<>;


#parsing the metal layer (digits)
my ($num_1)=$input1=~ m/(\d)+/;
my ($num_2)=$input2=~ m/(\d)+/;

#Ony exception, no equal metal layers
if ($num_1 == $num_2){ 
    say "You cannot do a layout  the same layer\n";
    exit;
}


metal_stack_order($num_1,$num_2);

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Thanks for the help!

Replies are listed 'Best First'.
Re: Can't figure out how to include LAST member of the array
by haukex (Archbishop) on Feb 09, 2021 at 19:41 UTC

    How about print "M$End\n"; after the for loop? And note you talk about an array but your code doesn't include one (for output, that is), but I assume you'd probably want to push elements onto a new array instead of printing them.

    BTW, your regexes for getting the numbers from the input aren't quite right, the + quantifier needs to be inside the capture group, and since you're already using regexes, you can use them for validation too. For example, my ($num_1) = $input1 =~ m/^m(\d+)$/i or die "bad input: $input1";

    A few edits shortly after posting.

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      You're right, I want to push it into some hash once I knew how to tackle the last element. I will make that change and for my regex as well. Update: I think I am going to create a table for the values of each metal and via then reference those from a table. Not sure how I will do that yet. I will try. thanks!

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Re: Can't figure out how to include LAST member of the array
by jdporter (Paladin) on Feb 09, 2021 at 20:27 UTC

    How about adding a 

    print "M$End";

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    after the for loop?

    That is: 

        for (my $i=$Start; $i <= ($End-1) ; $i++){        
        print "M$i --> V$i-->";
    }
    print "M$End";

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    But if I were doing this, I'd probably do it like so: 

        for (my $i=$Start; $i <= $End; $i++) {
        print "M$i";
        print " --> V$i-->"   unless $i == $End;
    }

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      Thanks for the help. I did not know I could write the unless condition this way. I will try that! Thanks

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Re: Can't figure out how to include LAST member of the array
by kcott (Archbishop) on Feb 10, 2021 at 05:10 UTC

    G'day perlynewby,

    "IS there a Perl library that I can use for that??"

    List::MoreUtils has a zip (aka mesh) function which you could use something like this: 

    $ perl -e '
    use strict;
    use warnings;
    use List::MoreUtils "zip";
    my @sorted = 1..5;
    my @M = map "M$_", @sorted;
    my @v = map "v$_", @sorted[0..$#sorted-1];
    print join "->", grep defined, zip @M, @v;
'
M1->v1->M2->v2->M3->v3->M4->v4->M5

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    — Ken

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