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How do i create array of arrays

by Anonymous Monk
on Jan 13, 2001 at 03:25 UTC ( [id://51501]=perlquestion: print w/replies, xml ) Need Help??

Anonymous Monk has asked for the wisdom of the Perl Monks concerning the following question: (arrays)

I have two de refrenced arrays like $a and $b. Now i have to create another master dereferenced array with this two arrays. Can anyone help me. Thank You, - bari

Originally posted as a Categorized Question.

Replies are listed 'Best First'.
Re: How do i create array of arrays
by extremely (Priest) on Jan 13, 2001 at 08:05 UTC
    my $a = [ "mark", 1, 2, "three"]; #anon array my @b = ( "anon", 3, 4, "five"); #named array my $b = [@b]; #anon array from named my $c = [ $a, [@b], $b, [ "werd", 5, 6, "seven" ] ]; my @d = ( $a, $b, $c->[3] ); print "$d[2]->[3] and $c->[3][3]\n";

    Does that help? () make lists, [] make anon arrays, you can nest anon arrays easily to make nested structures.

    Edited by davido to correct mismatched bracket types.

Re: How do i create array of arrays
by robsv (Curate) on Jan 17, 2001 at 00:18 UTC
    # Create the arrays my $a = [qw(one two three four)]; my $b = [qw(red green blue)]; # Create the array of arrays my $aoa = [$a,$b]; # Print each element foreach $i (0..$#{$aoa}) { foreach $j (0..$#{$aoa->[$i]}) { print $aoa->[$i][$j] . "\n"; } }
Re: How do i create array of arrays
by Adam (Vicar) on Jan 13, 2001 at 07:08 UTC
    my @array = ( 1..3 ); my $arrayRef = \@array; my @arrayOfArrays = ($arrayRef); print $arrayOfArrays[0]->[1];
    I hope that helps.

    {Editor note by davido: This approach is risky. For one thing, if @array ever changes, its changes will affect @arrayOfArrays. Thus, if you build up an array of arrays using this method inside of a loop, you could end up with multiple instances of the same @array, rather than multiple distinct and unique arrays as the contents of the @arrayOfArrays. Using my within the loop will create a new @array each time through, but better to be explicit about it rather than relying on lexical scoping which can confuse the reader later on.

    Changing the second line to:

    my @arrayRef = [@array];
    will solve the potential problem.

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