Troubles with Unshift and Push

nat47 has asked for the wisdom of the Perl Monks concerning the following question:

This is probably a dumb question. I am trying to take a list of @num_weights and add one number from @leftovers to the front, save it in a @hold_generations array, for all @leftovers. The code is:

my @num_weights = [36,264,188];
my @leftovers = [1,2,3,4];
my @hold_generations;
 my $i = 0;
        
        for(my $p = 0; $p < 1;$p++) #Go through all leftovers
            {
                my $pick = $leftovers[$p];
                unshift @num_weights, $pick; #add item
                say Dumper(@num_weights);
                push @hold_generations, @num_weights; #store new array
                say Dumper(@hold_generations);
                splice @num_weights, 1, 1; #undo adding item
                say Dumper(@num_weights);
                
                 
            }
[download]

However, I am getting this result from Dumper()

Shouldn't Var1 be 1,36,264,188? That's whay I'm trying to get!

I'm sure there is a better way to do this, but I'd really just like to know whats going on.

My goal is to use bigger data sets and later on check @hold_generations for specific instances and then use that instance to re-run this whole thing.

Comment on Troubles with Unshift and Push Select or Download Code

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Re: Troubles with Unshift and Push by vinoth.ree (Monsignor) on Mar 04, 2015 at 05:18 UTC
Is this is correct way of creating array with three elements?, Did you try printing the values in `@num_weights` array? `my @num_weights = [36,264,188]; my @leftovers = [1,2,3,4];` [download] *All is well. I learn by answering your questions...*	[reply] [d/l] [select]
Re^2: Troubles with Unshift and Push by nat47 (Sexton) on Mar 04, 2015 at 05:19 UTC
Yeah, `say Dumper(@num_weights)`shows whats in the array.	[reply] [d/l]
Re^3: Troubles with Unshift and Push by vinoth.ree (Monsignor) on Mar 04, 2015 at 05:27 UTC
But it creates array with one element with anonymous array. *All is well. I learn by answering your questions...*	[reply] [d/l]
Re^4: Troubles with Unshift and Push by nat47 (Sexton) on Mar 04, 2015 at 05:30 UTC
Re^5: Troubles with Unshift and Push by vinoth.ree (Monsignor) on Mar 04, 2015 at 05:31 UTC
Some notes below your chosen depth have not been shown here
Re: Troubles with Unshift and Push by ipherian (Novice) on Mar 04, 2015 at 23:49 UTC
The bracket operator around data creates an array reference. `my @num_weights = [36,264,188];` [download] At this point, @num_weights has a single scalar element, which is itself a reference to another array. Same as: `my @sub_array = (36,264,188); ##real array my @num_weights = (\@sub_array); ##real array containing 1 reference` [download] Btw backslash is the make-reference operator Use parentheses to declare your arrays and it should work. This modified code: `my @num_weights = (36,264,188); my @leftovers = (1,2,3,4); my @hold_generations; my $i = 0; for(my $p = 0; $p < 1;$p++) #Go through all leftovers { my $pick = $leftovers[$p]; unshift @num_weights, $pick; #add item say Dumper(@num_weights); }` [download] Prints: `$VAR1 = 1; $VAR2 = 36; $VAR3 = 264; $VAR4 = 188;` [download]	[reply] [d/l] [select]