in reply to Re: Working With Arrays and Files
in thread Working With Arrays and Files

thanks for your help dave..... i'm still a lil unsure what this does 
my $key = pop @fields; #is this the same as chomp?
my $line = [@fields];  

@$line #could you briefly explain the naming convension here?

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and when i print it out, my columns are of different lengths, is there any way i can format it such that it comes out as straight columns? thanks again for your help....

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Re: Re: Re: Working With Arrays and Files
by dpuu (Chaplain) on Jul 23, 2002 at 21:18 UTC
    OK,

    First, I create the @fields array, using the split function with default args (i.e. splits $_ into fields separated by whitespace).

    Then, I use the pop function to remove (and get) the rightmost element of the fields array. (push and pop manipulate the right hand side; shift and unshift manipulate the left). So after the $key has been popped, @fields is an array of all fields, except the rightmost.

    To push a list onto a list of arrays, I need an array reference. I could have used \@fields; but there are subtle ways that can go wrong when you're new to perl data-structures. So instead, I create a new anonymous array reference (using square brackets).

    Later, when I want convert the array-reference back into an array, I need to use the array dereferencing operator: @{$line}. I appologise for using a standard shorthand here: perl interprets @$line as @{$line}.

    Your last question is how to format you colmns more nicely. The easiest way (might work) is to join the elements of the array using a tab, instead of a space: 

        my $text = join("\t", @fields);

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    If this doesn't work, then there are many alternatives: you could define a format (see books); or you could write some clever padding functions; or you could store the original input text in the hash-of-lines; or you could get a CPAN module such as Data::ShowTable or Text::FormatTable. Personally, I usually don't bother: if I really need to view something as neat tables, then I use a table viewing application (or output as html). --Dave.
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      is there any way i can incorporate printf instead of the join?
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        Of course. So long as you know how many fields are in the array, instead of join(" ", @fields), you could say: 
          printf "%s  %s  %d  %s %d", @fields;

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        --Dave.
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