$_ iterates through that list (but why wasn't my original say for iterating through the list?)
@ dereferences the array (again, why didn't my original @{...} dereference it?)
It was iterating through the list and it did dereference , but the number 2 is not an array reference, so the list was empty :) strict noticed this problem, so it ended your program . This is why we love strict.
Whatever text you're learning from, you need to go back and do the exercises you skipped :) the only way to absorb and remember is by typing it yourself :)
$ perl -E " say for [1..4],[5..8] "
ARRAY(0x3f8adc)
ARRAY(0x9b9eac)
aww, array references stringify like that, to get at the values, we need to dereference
Trying it your way
$ perl -E " say for @{ [1..4],[5..8] }"
5
6
7
8
Aww, it only printed the contents of the last reference. To print both, we need to iterate over a list of reference, not a list of values
$ perl -E " say @$_ for [1..4],[5..8] "
1234
5678
Oh look, the numbers are all joined together, thats how say works
$ perl -E " say 1,2,3,4; say 5..8; "
1234
5678
I know, we'll put it in double quotes string, that will improve it
$ perl -E " say qq{@$_} for [1..4],[5..8] "
1 2 3 4
5 6 7 8
Now for the brackets
$ perl -E " say qq{[@$_]} for [1..4],[5..8] "
[1 2 3 4]
[5 6 7 8]
Now for the comma by changing the $", the LIST_SEPARATOR (the \" is for my shell, cmd.exe )
$ perl -E " local $\"=q{,}; say qq{[@$_]} for [1..4],[5..8] "
[1,2,3,4]
[5,6,7,8]
Even if we employ $" properly by limiting the scope of the changes with local, its better to use join function
$ perl -E " say q{[}, join( q{,}, @$_ ), q{]} for [1..4],[5..8] "
[1,2,3,4]
[5,6,7,8]
The values function is context sensitive
$ perl -E " %f = 6..9; say for values %f; "
9
7
$ perl -E " %f = 6..9; say for scalar values %f; "
2
Using @{} puts values %f in scalar context, just like the scalar function. This makes the values function return the number of values in %f; The number of values is not an array reference.
To learn more about context see Tutorials: Context in Perl: Context tutorial,
or see the free book Modern Perl, a loose description of how experienced and effective Perl 5 programmers work....You can learn this too. | 