Why does this function show an array of an array instead of just an array?

Question

use warnings;
use strict;

testfunc();
sub testfunc {
    my @first_pin_name_list=qw(
        VDD2_DDR2_S2_4
        VDD1_DDR2_S2_2
    );

    my @second_pin_name_list=qw(
        VDD2_DDR2_S2_4
        VDD1_DDR2_S2_2
    );
    my @expected_list =qw(
        VDD1_DDR0_S2_[2:1]
        VDD2_DDR0_S2_[5:1]
    );

    my @listoftests = ( 
        {INPUT_LIST => \@first_pin_name_list,OUTPUT_LIST => \@expected_list,OK_2_FAIL=> 0}, 
        {INPUT_LIST => \@second_pin_name_list,OUTPUT_LIST => \@expected_list,OK_2_FAIL => 1}

    );  

    print @expected_list;

    # should show an array but instead debugger shows an array of an array
    my @listtotest = $listoftests[0] -> {INPUT_LIST};
    print "hello";
    return @listoftests;
}

The debugger shows @listtotest containing an array of an array, but I want to see just an array with elements. How can I change my code to show just an array of elements?

I'm guessing the debugger is showing you \@listtotest, so that's the top level reference. Others, it would treat each element separately. — brian d foy
– brian d foy, Commented Jun 10, 2020 at 4:11

ysth · Accepted Answer · 2020-06-10 03:54:38Z

6

You aren't showing us what the debugger is showing you, but there is no array of arrays.

$listoftests[0]->{INPUT_LIST} is a reference to an array, @first_pin_name_list. If you want to assign the elements in that array to @listtotest, you need to dereference it:

my @listtotest = $listoftests[0]->{INPUT_LIST}->@*;

or on older perls:

my @listtotest = @{ $listoftests[0]->{INPUT_LIST} };

answered Jun 10, 2020 at 3:54

ysth

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4 Comments

user12006938 Over a year ago

apologies how can I add pictures on SO? Id like to know for future reference. Ill try this out. this may solve my problems.

ysth Over a year ago

can't you copy and paste from the debugger? though I've seen pictures, I have no idea how and find pictures not very useful

user12006938 Over a year ago

ah ok. I can copy from the debugger, just thought it would not look clean on here.

Yunnosch Over a year ago

Here is help on making things look clean here stackoverflow.com/editing-help

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