While merlyn has suggested the best answer (don't re-invent the wheel), that doesn't help you if your reason for doing this is to learn how the wheel was made to begin with.

In this case, I can see one immediate problem which Sort::Field isn't going to help you with: dealing with the string v. numeric form of the data. I don't have a good answer to that problem, either.

For something like this, the first-draft of my version of this wheel would look something like so, assuming string-comparison was sufficient: 

# $n contains field to sort on
# records to sort are in @ARGV
my @records;
while (<>) {
  # chomp deleted so we don't have to add \n later
  push @records, [ split ',' ];
}
# now sort them;
@records = sort { $$a[$n] cmp $$b[$n] } @records;
# now print them
foreach $record (@records) {
  print join (',',@$record);
}

[download]
The first loop reads in the CSV records, crudely splits them on commas, stores the results in an anonymous array, which it adds to the @records array. This is not robust -- it'll fail when the fields of the record contain quoted commas -- but for a first cut, it'll do the job.

The sort line sorts the @records array using the code block given as the comparison function. In this case, since we know that each element of @records is a reference to an array, with each sub-array element being one of the original fields, we can access the nth field with $$a[$n], so the comparison function simply compares the nth field of the two records.

Finally, we output the now-sorted array.

In reply to RE: sorting comma separated value file by BlaisePascal
in thread sorting comma separated value file by taopunk

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