Perl Array of Arrays

A Perl Array of Arrays is a Perl array data structure that is an Array of Arrays Data Structure (whose array elements are all Perl Array Data Structures).

• AKA: Perl List of Lists.
• Example(s):
  • a Perl-based Matrix, such as @AoA1 = ([3, 1, 4], [2, 5, 11], [1, 7, 4])
• Counter-Example(s):
  • a Perl Array of Hashes.
  • a Perl Hash of Arrays.
  • a Python List of Lists.
• See: Perl Coding Example, Matrix Data Structure, Multidimensional Array.

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References

• http://perldoc.perl.org/perldsc.html#ARRAYS-OF-ARRAYS

2010

• (Melli, 2010) ⇒ Gabor Melli. (2010). “Perl Array of Arrays - Examples." GM-RKB

Populate manually

   my @AoA1 = ([3, 11, 4], [2, 5], [1, 72, 4, 8], );
   my @AoA2 = (["A", \@Vector1], ["B", \@Vector2], ["C", \@Vector3] );

Populate from a file.

   my @AoA3 ;
   while (<>) {
      my @tmp = split;        # Split elements into an array.
      print "tmp=[@tmp]\n" ;
      push @Array3, @tmp ;    # Append the elements to the Array
      push @AoA3, [ @tmp ];   # Add an anonymous array reference to @AoA.
   }

Push into an explicit array index.

   push @{ $AoA[$index] }, "apple", "banana" ;
   push @{ $AoA[$index] }, @record ;

Other alternatives

   $AoA[$i] = [ @array ];   # Safest, sometimes fastest
   $AoA[$i] = \@array;      # Fast but risky, depends on my-ness of array
   @{ $AoA[$i] } = @array;  # A bit tricky

Print

   print "Array max index = [$#AoA]\n" ;
   for my $i (0 .. $#AoA) {
      for $j (0 .. $#{ $AoA[$i] } ) {
         print "element $i $j is $AoA[$i][$j]\n";
      }
   }

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