'split'-ting headache

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

Hi, I am writing a script which reads in a file containing 16 columns of data. I am then using 'split' to read the data into an array and split it into elements based on where the whitespace in the file is e.g. between each column of data. My problem is that when i test that split has worked by printing out an element of the array - the output is a mixture of data from different elements; here's a snippit of the code;

while (<FILE>)
{
        $line = $_;
        chomp ($line);

        @array = ();
        @array = split (/\s+/, $line);   
    print $array[8];
}
[download]

i dont understand where i am going wrong with split. thanks x

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Re: 'split'-ting headache by Joost (Canon) on Jun 11, 2002 at 14:31 UTC
You very likely have 'empty' columns in your data which get eaten up by your \s+ match. `@array = split (/ /, $line);` [download] Should work, if you don't have spaces in your data. (remember that split(/ /) is different from split() or split(" ") - read `perldoc -f split` ) Update: this code assumes you have exactly one space between columns, adjust as needed. `-- Joost downtime n. The period during which a system is error-free and immune from user input.` [download]	[reply] [d/l] [select]
Re: Re: 'split'-ting headache by Anonymous Monk on Jun 11, 2002 at 14:39 UTC
unfortunately i do have spaces (which vary in length) in my data so that wont work Joost. the output i am expecting is just to select certain numbers from elements if they pass a certain criteria e.g if $array[[0]] > 95 && $array[8] =~ /hello/	[reply]
(jeffa) 3Re: 'split'-ting headache by jeffa (Bishop) on Jun 11, 2002 at 15:00 UTC
Then what you need to do is inspect your data. I was working on similar problem recently and finally noticed that i had a few records with ~~trailing~~ leading* space - that is, a space or two before any data. Use Data::Dumper to inspect your arrays (and use strict!): `use strict; use Data::Dumper; while (my $line = <FILE>) { chomp ($line); #$line =~ s/^\s//; my @array = split(/\s+/,$line,16); print Dumper \@array; }` [download] Also, notice that i used the third argument for split - LIMIT. Since you know that you need 16 elements, explicitly let Perl know. If you do find that trailing space is the culprit, you can uncomment the commented line from above. Good luck! thanks particle ;) jeffa L-LL-L--L-LL-L--L-LL-L-- -R--R-RR-R--R-RR-R--R-RR B--B--B--B--B--B--B--B-- H---H---H---H---H---H--- (the triplet paradiddle with high-hat)	[reply] [d/l]
Re: 'split'-ting headache by Abigail-II (Bishop) on Jun 11, 2002 at 14:28 UTC
There doesn't seem to be anything wrong with your code. What is your input, what is your output, and what did you expect as output? Abigail	[reply]