Aack! My email client (mail.yahoo.com) has substituted all for the 'backslash' n's
with literal
newlines, thus making my code virtually unreadable. I hope this hasn't happened to
anyone else,
or what you read below may be very confusing.
--- Curtis Poe <[EMAIL PROTECTED]> wrote:
> --- Roy Peters <[EMAIL PROTECTED]> wrote:
> > hi,
> >
> > I have the following string
> >
> > $a =
> > "buy 10/23/01 100 12.625 50 25.25
>
> > buy 10/25/01 100 12.625 50 25.25
>
> > buy 09/1/01 100 12.625 50 25.25
>
> > buy 1/23/01 100 12.625 50 25.25
> ";
> >
> > I would like to sort this by the date (ie the second field) in the
> > above string.
> >
> > So it looks like this:
> >
> > $a =
> > "buy 1/23/01 100 12.625 50 25.25
> ";
> > buy 09/1/01 100 12.625 50 25.25
>
> > buy 10/23/01 100 12.625 50 25.25
>
> > buy 10/25/01 100 12.625 50 25.25
> ;
> >
> > What's the cleanest way to do this?
>
> Roy,
>
> You need to be *extremely* specific about how your input and output should look.
>Your input,
> for
> example, has a
> followed by a newline. That interpolates as two newlines between each record.
>Further, all
> records after the first have a space before the word 'buy'. Is this truly
>reflecting your data?
>
> Your output is also not valid Perl. I'll show you what I came up with, but it's
>going to be
> difficult to maintain if you're not familiar with map and sort.
>
> ##########################################
> use strict;
> use Data::Dumper;
>
> my $data = "buy 1/23/01 100 12.625 50 25.25
>
> buy 09/1/01 100 12.625 50 25.25
>
> buy 10/23/01 100 12.625 50 25.25
>
> buy 10/25/01 100 12.625 50 25.25
> ";
>
> my @data = split /
>
> /, $data;
>
> @data = map { join ' ', ( $_->[0], ( join '/', @{$_->[1]} ), $_->[2] ) }
> sort { $a->[1][2] <=> $b->[1][2] || $a->[1][0] <=> $b->[1][0] ||
>$a->[1][1] <=> $b->[1][1] }
> map { [ $_->[0], [split ///, $_->[1]], $_->[2] ] }
> map { [split( /s+/, trim( $_ ), 3) ] } @data;
> print Dumper @data;
>
> sub trim {
> my $data = shift;
> $data =~ s/^s+//;
> $data =~ s/s+$//;
> return $data;
> }
> ##########################################
>
> I was going to clean that up and document it, but then I realized that since I was
>unsure as to
> whether or not my understanding of your input was accurate, I could be spending a
>lot of time
> explaining something that doesn't fit what you need. Regardless, here's a brief
>explanation:
>
> I split the data on two newlines (since this is what you have).
>
> The first map in the Schwartzian transform (read them bottom to top) splits the data
>on spaces
> (after trimming out extraneous beginning and closing whitespace) and uses splits
>optional 3rd
> parameter to limit the split to three scalars:
>
> This:
> ' buy 10/25/01 100 12.625 50 25.25 '
> Becomes:
> 'buy', '10/25/01', '100 12.625 50 25.25'
>
> The next map splits the second element (the date) on the forward slash and creates
>an array ref
> for that element.
>
> The sort sorts on the year, then the month, then the day.
>
> The last map then puts the string back together. Note that the beginning and ending
>whitespace
> is
> lost. If that's important, you'll need to modify this solution.
>
> I realize that this is probably very confusing if you haven't used this before, so I
>offer my
> apologies. If you have show us your *exact* input data and the code that reads it,
>we can
> probably offer an easier to follow solution.
>
> Cheers,
> Curtis "Ovid" Poe
>
> =====
> Senior Programmer
> Onsite! Technology (http://www.onsitetech.com/)
> "Ovid" on http://www.perlmonks.org/
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