To learn about arrays, and more importantly, why there are no true two dimensional arrays, please read perldata, perlref, perllol, and perldsc. You can skim through the last two (for now), but basically you need to read perlref cause all an AoA (Array of Arrays) is, is an Array of Array references, and you'll need to know all about references.

Second, you'll need to visit your local documentation and read perlfunc, and take a good look at the function split (you'll probably wanna split on whitespace).

That will get you to the point where you can manipulate the data, and populate your data structure as you wish (your AoA).

If you don't know how to open a file, well it's back to perlfunc, and in this case, you're looking for open.

If that is truly the case, you're best off reading perlfaq first, and investing in a book.

If at any point you need further guidance into wading through the documentation, or if you simply don't know all the vast perl resources that are available to you, How to RTFM covers pretty much all of them.

 

______crazyinsomniac_____________________________ Of all the things I've lost, I miss my mind the most. perl -e "$q=$_;map({chr unpack qq;H*;,$_}split(q;;,q*H*));print;$q/$q;"

Unless the data is sequential and non-sparse a hash would be better suited for this than an array.

The following is a simple example to get you started:

    #!/usr/bin/perl -w

    use strict;

    my %hash;

    while (<DATA>) {
        chomp;
        next unless /\S/; # Skip blank lines
        /(\d+)/;          # Match the first number
        $hash{$1} = $_;
    }


    for my $key (sort {$a <=> $b} keys %hash) {
        print $key, "\t", $hash{$key}, "\n";
    }

    # Prints:

    # 1       1 2 3 4 5 
    # 10      10 20 30 40 50
    # 200     200 100 300 2 1

    __DATA__
    1 2 3 4 5 
    10 20 30 40 50
    200 100 300 2 1
[download]

You might also wish to split the data on each line and store it as an array ref in the hash. Have a look at the perldsc manpage for more information.

--
John.

001    use strict;
002    my @array;
003    open (INFILE, "<filename") or die "could not open file";
004    foreach (<INFILE>) {
005        chomp;
006        push @array, [m/(\d+)/, $_];
007    }
008    close INFILE;
[download]

Line by line explaination:

Line 1: rule #1 always use strict it will save you hours in the long run.

Line 2: Create a place to put our answers

Line 3: open your data file INFILE is now the file handle for your data file. Relplace "filename" with the name of your file. It is good practice to always check the results of an open open will return a false value if it fails and a true value if it suceeds the right side of the or will never happen if it suceeds but we will die if it fails.

Line 4: The diamond operator  <> reads one line from INFILE and sets the value of $_ to that string.

Line 5: chomp the newline off the end of $_

Line 6: Line noise? Let's break it down. push @array, will add whatever comes after the comma to the end of @array, "push" them on to the end. What is it pushing? Well the square brackets [] will turn whatever is inside of them into an anonymous array. This anonymous array will be push onto the end of @array. So Line 6 could be rewritten as

    $_ =~ m/(\d+)/; #set $1 to the first group of digits
    push @array, [$1, $_];
[download]

    $_ =~ m/(\d+)/;
    my @subarray = ($1, $_);
    push @array, [@subarray];
[download]

    $_ =~ m/(\d+)/;
    my @subarray = ($1, $_);
    push @array, \@subarray;
[download]

Line 7: End of for loop

Line 8: close the file

Anyway,
$array[0][0] will be "1"
$array[0][1] will be "1 2 3 4 5"
$array[1][0] will be "10"
$array[1][1] will be "10 20 30 40 50"
$array[2][0] will be "200"
$array[2][1] will be "200 100 300 2 1"

--

flounder

One more quick question ! If my NASTRAN output file was something like this:

1 2 3 4 5

1 20 30 40 50

1 9 3 3 6

4 6 7 9 0

4 4 8 90 8

4 5 2 7 20

9 5 2 7 20

9 20 30 40 50

9 4 8 90 8

The start of each line (The first number) represent an element ID. Would it possible to create a hashes of nested arrays where each element ID is the key for the created nested array. I know it does not make sense, but I need a seperate nested array for each element ID (start of each line) so that I can sort it later on based on a chosen column and print it. I have to get the all the lines that starts with first element put them in a nested array in a way which is described in the first message and later create a hash where the key is the element ID and points to a nested array which has all the information about that particular element. Basically: Element ID (key for the hash) = 1 points to a nested array of

1 '1 2 3 4 5'

1 '1 20 30 40 50'

1 '1 9 3 3 6'

Element ID = (key for the hash) = 4 points to a nested array

4 '4 6 7 9 0'

4 '4 4 8 90 8'

4 '4 5 2 7 20'

Element ID = (key for the hash) = 9 points to a nested array

9 '9 5 2 7 20'

9 '9 20 30 40 50'

9 '9 4 8 90 8'

I am not sure if this is the best way of doing it but I can not think of any other way. Any Help will be appreciated. Thanks a lot.

Thanks flounder99, it works!, and thanks for the detailed explanation!