Feature Request: `:adverb` to capture/return original CSV column-order.

[jubilatious1]

Feature Request: :adverb to capture/return original CSV column-order.

Hi, maybe I'm not "getting" the Text::CSV way of doing things, but one thing that is different between Perl5 and Raku is that Raku guarantees hash randomization.

Therefore, any method capturing "CSV_header" separate from "CSV_datarows" needs to retain column-order otherwise to a new user it appears that Raku hopelessly scrambles CSV columns, with no way of restoring.

Example below using a classic CSV from Microsoft: https://www.microsoft.com/en-us/download/details.aspx?id=45485

admin@MBP ~ % cat Import_User_Sample_en.csv
User Name,First Name,Last Name,Display Name,Job Title,Department,Office Number,Office Phone,Mobile Phone,Fax,Address,City,State or Province,ZIP or Postal Code,Country or Region
chris@contoso.com,Chris,Green,Chris Green,IT Manager,Information Technology,123451,123-555-1211,123-555-6641,123-555-9821,1 Microsoft way,Redmond,Wa,98052,United States
ben@contoso.com,Ben,Andrews,Ben Andrews,IT Manager,Information Technology,123452,123-555-1212,123-555-6642,123-555-9822,1 Microsoft way,Redmond,Wa,98052,United States
david@contoso.com,David,Longmuir,David Longmuir,IT Manager,Information Technology,123453,123-555-1213,123-555-6643,123-555-9823,1 Microsoft way,Redmond,Wa,98052,United States
cynthia@contoso.com,Cynthia,Carey,Cynthia Carey,IT Manager,Information Technology,123454,123-555-1214,123-555-6644,123-555-9824,1 Microsoft way,Redmond,Wa,98052,United States
melissa@contoso.com,Melissa,MacBeth,Melissa MacBeth,IT Manager,Information Technology,123455,123-555-1215,123-555-6645,123-555-9825,1 Microsoft way,Redmond,Wa,98052,United States

Above, column order is User Name, First Name, Last Name, Display Name, Job Title, Department, Office Number, Office Phone, Mobile Phone, Fax, Address, City, State or Province, ZIP or Postal Code, Country or Region

---

Text:CSV code below generally from the docs; column order is re-arranged to alphabetical: address, city, country or region, department, display name, fax, first name, job title, last name, mobile phone, office number, office phone, state or province, user name, zip or postal code

admin@MBP ~ %  raku -MText::CSV -e 'my $csv = Text::CSV.new;
                                    my $fh  = open "Import_User_Sample_en.csv", :r, :!chomp;  
                                    my @hdr = $csv.header($fh, munge-column-names => "fc").column-names;
                                    my @rows = $csv.getline_hr_all($fh); .say for @rows;'
{address => 1 Microsoft way, city => Redmond, country or region => United States, department => Information Technology, display name => Chris Green, fax => 123-555-9821, first name => Chris, job title => IT Manager, last name => Green, mobile phone => 123-555-6641, office number => 123451, office phone => 123-555-1211, state or province => Wa, user name => chris@contoso.com, zip or postal code => 98052}
{address => 1 Microsoft way, city => Redmond, country or region => United States, department => Information Technology, display name => Ben Andrews, fax => 123-555-9822, first name => Ben, job title => IT Manager, last name => Andrews, mobile phone => 123-555-6642, office number => 123452, office phone => 123-555-1212, state or province => Wa, user name => ben@contoso.com, zip or postal code => 98052}
{address => 1 Microsoft way, city => Redmond, country or region => United States, department => Information Technology, display name => David Longmuir, fax => 123-555-9823, first name => David, job title => IT Manager, last name => Longmuir, mobile phone => 123-555-6643, office number => 123453, office phone => 123-555-1213, state or province => Wa, user name => david@contoso.com, zip or postal code => 98052}
{address => 1 Microsoft way, city => Redmond, country or region => United States, department => Information Technology, display name => Cynthia Carey, fax => 123-555-9824, first name => Cynthia, job title => IT Manager, last name => Carey, mobile phone => 123-555-6644, office number => 123454, office phone => 123-555-1214, state or province => Wa, user name => cynthia@contoso.com, zip or postal code => 98052}
{address => 1 Microsoft way, city => Redmond, country or region => United States, department => Information Technology, display name => Melissa MacBeth, fax => 123-555-9825, first name => Melissa, job title => IT Manager, last name => MacBeth, mobile phone => 123-555-6645, office number => 123455, office phone => 123-555-1215, state or province => Wa, user name => melissa@contoso.com, zip or postal code => 98052}

How to output a CSV file in the original column order?

[Tux]

🐧 cat kh.raku
#!raku

use v6;
use Slang::Tuxic;

use Data::Dump;
use Text::CSV;

my $csv  = Text::CSV.new;
my $fh   = open "test.csv", :r, :!chomp;  
my @hdr  = $csv.header ($fh, munge-column-names => "fc").column-names;
.say for @hdr;
my @rows = $csv.getline_hr_all ($fh);

.say for @rows;
$_{@hdr}.say for @rows;

🐧 cat test.csv
c_species,species,legs
1,cat,4
2,caterpillar,6
3,spider,8
4,human,2

🐧 raku kh.raku
c_species
species
legs
{c_species => 1, legs => 4, species => cat}
{c_species => 2, legs => 6, species => caterpillar}
{c_species => 3, legs => 8, species => spider}
{c_species => 4, legs => 2, species => human}
(1 cat 4)
(2 caterpillar 6)
(3 spider 8)
(4 human 2)

I agree however that $csv.csv (in => @rows, headers => @hdr, out => $*OUT); should be improved

[jubilatious1]

I can retain original column order using various calls to Raku's pairs routine.

This basically lets Text::CSV parse the file linewise and forces the end-user to write code to select individual columns, etc.:

#!raku

use Text::CSV;

my $csv  =  Text::CSV.new;
my $fh   =  open "Import_User_Sample_en.csv", :r, :!chomp;  

my @hdr2 =  $csv.header($fh, munge-column-names => "uc").column-names.pairs; 
#say |@hdr2.map: *.values;

my @rows;
for $fh.lines() { $csv.getline($_) andthen @rows.push: $_.pairs } ;

#$_>>.values.put for [@hdr2,|@rows]; #return entire file (parsed);
$_>>.values[0].put for [@hdr2,|@rows]; #return first column only (w/ header);

Unfortunately I keep running into the dreaded The iterator of this Seq is already in use/consumed by another Seq error, so I cannot show you both outputs at the bottom. So here's the first column (second output above):

USER NAME
chris@contoso.com
ben@contoso.com
david@contoso.com
cynthia@contoso.com
melissa@contoso.com

If the code above can be adapted, maybe an adverb/named-argument can be added with the default:

re-order => False

?? Thx.

[Tux]

I have the stable order fixed in a new branch, but that caused a new failure in fragments that I cannot explain. Tuits fail at this moment.

On advice of Liz I also changed the type declarations from returns ABC::XYZ to --> ABC::XYZ, which seems to cause speed penalty of 10%.

[lizmat]

On advice of Liz I also changed the type declarations from returns ABC::XYZ to --> ABC::XYZ, which seems to cause speed penalty of 10%.

What??

I can't reproduce that.

% time raku -e 'sub a() returns Int { 42 };   a for ^100000000'
real	1.24s
user	1.24s
sys	0.02s
% time raku -e 'sub a(--> Int) { 42 };   a for ^100000000'
real	1.24s
user	1.23s
sys	0.02s

Can you? If so, please provide a golf!

[jubilatious1]

~ % time raku -e 'sub a() returns Int { 42 };   a for ^100000000'
raku -e 'sub a() returns Int { 42 };   a for ^100000000'  0.82s user 0.06s system 87% cpu 1.004 total

~ % time raku -e 'sub a(--> Int) { 42 };   a for ^100000000'
raku -e 'sub a(--> Int) { 42 };   a for ^100000000'  0.84s user 0.06s system 97% cpu 0.929 total

MacOS Ventura 13.7.6
Rakudo™ v2023.05

[lizmat]

I'd say that's within noise levels?

[lizmat]

Also, I compared the QAST of the two case: and they are identical afaics