Sorting an Array

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

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Re: Sorting an Array by toolic (Bishop) on Jul 31, 2014 at 13:48 UTC
`perldoc -q sort` [download] How do I sort an array by (anything)?	[reply] [d/l]
Re: Sorting an Array by McA (Priest) on Jul 31, 2014 at 13:52 UTC
Hi, one part of this sorting job is the possibility to compare the values by which you want to sort. In this case the dates stored in `entry{statement_date}`. So you have to convert this date to a comparable value. What is the format of this date? McA	[reply] [d/l]
Re: Sorting an Array by choroba (Cardinal) on Jul 31, 2014 at 17:12 UTC
Note that creating an anonymous hash from lexical %entry is not needed. You can directly store a reference to it, as my will create a new one in the next iteration of the loop: `push @statements, \%entry;` [download] لսႽ† ᥲᥒ⚪⟊Ⴙᘓᖇ Ꮅᘓᖇ⎱ Ⴙᥲ𝇋ƙᘓᖇ	[reply] [d/l]
Re: Sorting an Array by burgerc (Novice) on Jul 31, 2014 at 18:27 UTC
Thanks everyone. The sorting script worked. Not sure I understand the last comment about using my %entry. I'm sure this may help in speed of script. So I would love some further clarification on that. Also I made a slight change in sorting script to get a descending order. here is the final code. `for (@{ $data->{'mail-item'} }) { my %entry; $entry{job} = $_->{'mail-jobnum'}; $entry{product} = $_->{'mail-prodnum'}; $entry{statement_date} = $_->{'mail-statement-date'}; push(@statements, {%entry}); } @statements = sort by_date @statements; $c->stash->{statements} = \@statements; sub by_date { my $dateA = $a->{statement_date}; my $dateB = $b->{statement_date}; $dateA =~ s!(\d\d)/(\d\d)/(\d\d\d\d)!$3$1$2!; $dateB =~ s!(\d\d)/(\d\d)/(\d\d\d\d)!$3$1$2!; $dateB cmp $dateA; }` [download]	[reply] [d/l]
Re^2: Sorting an Array by AppleFritter (Vicar) on Jul 31, 2014 at 18:35 UTC
Not sure I understand the last comment about using my %entry. I'm sure this may help in speed of script. So I would love some further clarification on that. This refers to the for loop where you're pushing entries onto your `@statement` array. You're explicitely constructing a named hash, `%entry`, each time, but this isn't necessary; you can just as well do this: `for (@{ $data->{'mail-item'} }) { push @statements, { job => $_->{'mail-jobnum'}, product => $_->{'mail-prodnum'}, statement_data => $_->{'mail-statement-date'} }; }` [download] Or, since you only have one statement in your loop body now, you can even use `for` as a statement modifier: `push @statements, { job => $_->{'mail-jobnum'}, product => $_->{'mail-prodnum'}, statement_data => $_->{'mail-statement-date'} } for (@{ $data->{'mail-item'} });` [download] Although I personally consider this less readable than the "regular" loop above.	[reply] [d/l] [select]
Re: Sorting an Array by burgerc (Novice) on Jul 31, 2014 at 16:19 UTC
the date format is 05/21/2014	[reply]
Re^2: Sorting an Array by Cristoforo (Curate) on Jul 31, 2014 at 16:43 UTC
Haven't tried it out, but I think this would sort them. `@statements = sort by_date @statements; sub by_date { my $dateA = $a->{statement_date}; my $dateB = $b->{statement_date}; $dateA =~ s!(\d\d)/(\d\d)/(\d\d\d\d)!$3$1$2!; $dateB =~ s!(\d\d)/(\d\d)/(\d\d\d\d)!$3$1$2!; $dateA cmp $dateB; }` [download]	[reply] [d/l]
Re^3: Sorting an Array by AppleFritter (Vicar) on Jul 31, 2014 at 17:04 UTC
You could also use a date parsing module such as Date::Parse and do a Schwartzian Transform: `use Date::Parse; # ... my @statements = map { $_->[1] } sort { $a->[0] <=> $b->[0] } map { [ str2time($_->{'statement_date'}), $_ ] } @statements;` [download] Other date-parsing modules that might be of interest include Date::Manip, HTTP::Date, and Time::ParseDate.	[reply] [d/l]
Re^4: Sorting an Array by choroba (Cardinal) on Jul 31, 2014 at 17:22 UTC