Hi I have a array as myarray. I would like to make a list as '1 2 3' which is joining the first subarray. My string is printing the memory location I suppose instead of list. any help will be appreciated.
@myarray = [[1,2,3],[4,5,6],[7,8,9]];
for (my $i=0; $i < @myarray; $i++) {
my @firstarray = $myarray[$i];
my $mystring = join("", @firstarray);
print "My string ".$mystring . ". "\n";
}
You have to dereference the inner array reference by @{ ... }. Also, do not use [...] for the top structure - use normal parentheses (square brackets create an array reference, not an array). There was also a problem with the concatenation on your print line:
@myarray = ( [1,2,3], [4,5,6], [7,8,9] );
for (my $i=0; $i < @myarray; $i++) {
my @firstarray = @{ $myarray[$i] };
my $mystring = join("", @firstarray);
print "My string " . $mystring . ".\n";
}
You should use the Data::Dumper module, that way, that will help you to know how to parse your data structure :
print Dumper \@myarray; # force passing array as ref
$VAR1 = [
[
[
1,
2,
3
],
[
4,
5,
6
],
[
7,
8,
9
]
]
];
But using the @ sigil (array) to store an ARRAY ref is strange, a $ sigil (scalar) is used most of the times for that purpose. (a reference is like a C pointer : an address to a memory cell. So its' a simple string, no need something else than a scalar to store it)
Then, you need to de-reference with the -> operator.
Ex :
$ perlconsole
Perl Console 0.4
Perl> my $arrayref = [[1,2,3],[4,5,6],[7,8,9]];
Perl> print join "\n", @{ $arrayref->[2] }
7
8
9
You actually have an array of array of array.
$myarray[0]$myarray[0][0..2]$myarray[0][0..2][0..2]You want
my @aoa = ([1,2,3],[4,5,6],[7,8,9]);
^ ^ ^ ^
| \------+------/
| 3 inner
1 outer
$aoa[$i][$j]
for my $inner (@aoa) {
print(join(', ', @$inner), "\n");
}
or
my $aoa = [[1,2,3],[4,5,6],[7,8,9]];
^^ ^ ^
| \------+------/
| 3 inner
1 outer
$aoa->[$i][$j]
for my $inner (@$aoa) {
print(join(', ', @$inner), "\n");
}
my @ and the []. Remember that [...] is basically do { my @a = (...); \@a }.AoA [3][3]my and 4 created with []), he doesn't have 3 inner and one outer. This can also bee seen with Dumper(\@myarray).You need to change how you initialize your array so that () is used for the outer array bounds and [] for the inner arrays, which means that they are declared as references that will later need to be cast into their native array format for processing (my @subarray = @{$myarray[$i]};)
my @myarray = ([1,2,3], [4,5,6], [7,8,9]);
for (my $i=0; $i < @myarray; $i++)
{
my @subarray = @{$myarray[$i]};
my $subarrayStr = join("", @subarray);
print $i.". Subarray Str = ".$subarrayStr."\n";
}
$myarray = [[1,2,3],[4,5,6],[7,8,9]];
printf "My string %s\n", join(" ", @{$myarray->[0]});
[[1,2,3],[4,5,6],[7,8,9]] returns a reference to the list of lists, not a list.
Change the @ into $ , to make $myarray a variable.
@{$myarray->[0]} will dereference the first sublist and return you the list you can use.
To print all three lists:
$myarray = [[1,2,3],[4,5,6],[7,8,9]];
map{printf "My string %s\n", join(" ",@{$_})} @{$myarray};
use warnings;-- that would have alerted you to your strange initialization for@myarray