perl push many array in one array - perl

Question

I have many short array
#seq1 /773..1447/ #seq2 /1 2 1843..1881 1923..2001/
but i use push
push(#add, #seq1);
push(#add, #seq2);
but it shows like it combine all array into one can't get each sub-array any more
/773..1447 1 2 1843..1881 1923..2001/
when i use
$number=#add;
it shows 6, but it should be 2. Can anyone explain the reason and how to change it.
When i use for loop to add each array
for(..){
#temp= split(/,/,$_);
push(#add, \#temp);
}
Then when i print #add; it only shows memory address, How can show all data in #add

Answer 1

This is normal behavior, use reference to #seq1 if you want #add to be two dimensional array,
push(#add, \#seq1);
To print all values in #add you should use Data::Dumper; print Dumper \#add;
The reason is that all parameters get flattened into list when they are pushed into array, so
#a = #b = (1,2);
push(#add, #a, #b);
is same as writing
push(#add, $a[0],$a[1], $b[0],$b[1]);
Check perlref and perllol for reference.

Answer 2

the push command takes an ARRAY and a LIST. It is important to understand what happens here.
The first argument must be an ARRAY, the one you want to push things on. After that it expects a LIST. What this means is that this push statement provides list context to any #seq_n array - and sort of expands the array into separate elements. So all the elements of the #seq_n are being pushed onto your #add.
Since you did not want that to happen, you wanted an array that holds the separate lists - what we call in Perl a List-of-Lists - you actually wanted to push a reference to your #seq_n arrays, using the \ character.
push #add, \#seq_1, \#seq_2, . . . \#seq_n;
Now you have an array that indeed holds references to each $seq_n.
To print them neatly, each sequence on its own line, you could iterate over each
foreach my $seq (#add) {
# $seq holds a reference to a list!
my $string = join " ", #$seq; # the # dereferences the $seq
print $string, "\n";
}
but TIMTOWTDI
print map {(join " ", #$_), "\n"} #add;
Always consider the context in Perl, and try to embrace the charms of join, grep and map.