package App::CSVUtils::csv_freqtable; use 5.010001; use strict; use warnings; our $AUTHORITY = 'cpan:PERLANCAR'; # AUTHORITY our $DATE = '2023-02-14'; # DATE our $DIST = 'App-CSVUtils'; # DIST our $VERSION = '1.010'; # VERSION use App::CSVUtils qw(gen_csv_util); gen_csv_util( name => 'csv_freqtable', summary => 'Output a frequency table of values of a specified field in CSV', description => <<'_', _ add_args => { %App::CSVUtils::argspec_field_1, }, examples => [ { summary => 'Show the age distribution of people', argv => ['people.csv', 'age'], test => 0, 'x.doc.show_result' => 0, }, ], on_input_header_row => sub { my $r = shift; # check arguments my $field_idx = $r->{input_fields_idx}{ $r->{util_args}{field} }; die [404, "Field '$r->{util_args}{field}' not found in CSV"] unless defined $field_idx; # this is a key we add to the stash $r->{freqtable} //= {}; $r->{field_idx} = $field_idx; }, on_input_data_row => sub { my $r = shift; $r->{freqtable}{ $r->{input_row}[ $r->{field_idx} ] }++; }, writes_csv => 0, on_end => sub { my $r = shift; my @freqtable; for (sort { $r->{freqtable}{$b} <=> $r->{freqtable}{$a} } keys %{$r->{freqtable}}) { push @freqtable, [$_, $r->{freqtable}{$_}]; } $r->{result} = [200, "OK", \@freqtable, {'table.fields'=>['value','freq']}]; }, ); 1; # ABSTRACT: Output a frequency table of values of a specified field in CSV __END__ =pod =encoding UTF-8 =head1 NAME App::CSVUtils::csv_freqtable - Output a frequency table of values of a specified field in CSV =head1 VERSION This document describes version 1.010 of App::CSVUtils::csv_freqtable (from Perl distribution App-CSVUtils), released on 2023-02-14. =head1 FUNCTIONS =head2 csv_freqtable Usage: csv_freqtable(%args) -> [$status_code, $reason, $payload, \%result_meta] Output a frequency table of values of a specified field in CSV. Examples: =over =item * Show the age distribution of people: csv_freqtable(input_filename => "people.csv", field => "age"); =back This function is not exported. Arguments ('*' denotes required arguments): =over 4 =item * B<field>* => I<str> Field name. =item * B<input_escape_char> => I<str> Specify character to escape value in field in input CSV, will be passed to Text::CSV_XS. Defaults to C<\\> (backslash). Overrides C<--input-tsv> option. =item * B<input_filename> => I<filename> (default: "-") Input CSV file. Use C<-> to read from stdin. Encoding of input file is assumed to be UTF-8. =item * B<input_header> => I<bool> (default: 1) Specify whether input CSV has a header row. By default, the first row of the input CSV will be assumed to contain field names (and the second row contains the first data row). When you declare that input CSV does not have header row (C<--no-input-header>), the first row of the CSV is assumed to contain the first data row. Fields will be named C<field1>, C<field2>, and so on. =item * B<input_quote_char> => I<str> Specify field quote character in input CSV, will be passed to Text::CSV_XS. Defaults to C<"> (double quote). Overrides C<--input-tsv> option. =item * B<input_sep_char> => I<str> Specify field separator character in input CSV, will be passed to Text::CSV_XS. Defaults to C<,> (comma). Overrides C<--input-tsv> option. =item * B<input_tsv> => I<true> Inform that input file is in TSV (tab-separated) format instead of CSV. Overriden by C<--input-sep-char>, C<--input-quote-char>, C<--input-escape-char> options. If one of those options is specified, then C<--input-tsv> will be ignored. =back Returns an enveloped result (an array). First element ($status_code) is an integer containing HTTP-like status code (200 means OK, 4xx caller error, 5xx function error). Second element ($reason) is a string containing error message, or something like "OK" if status is 200. Third element ($payload) is the actual result, but usually not present when enveloped result is an error response ($status_code is not 2xx). Fourth element (%result_meta) is called result metadata and is optional, a hash that contains extra information, much like how HTTP response headers provide additional metadata. Return value: (any) =head1 HOMEPAGE Please visit the project's homepage at L<https://metacpan.org/release/App-CSVUtils>. =head1 SOURCE Source repository is at L<https://github.com/perlancar/perl-App-CSVUtils>. =head1 AUTHOR perlancar <perlancar@cpan.org> =head1 CONTRIBUTING To contribute, you can send patches by email/via RT, or send pull requests on GitHub. Most of the time, you don't need to build the distribution yourself. You can simply modify the code, then test via: % prove -l If you want to build the distribution (e.g. to try to install it locally on your system), you can install L<Dist::Zilla>, L<Dist::Zilla::PluginBundle::Author::PERLANCAR>, L<Pod::Weaver::PluginBundle::Author::PERLANCAR>, and sometimes one or two other Dist::Zilla- and/or Pod::Weaver plugins. Any additional steps required beyond that are considered a bug and can be reported to me. =head1 COPYRIGHT AND LICENSE This software is copyright (c) 2023, 2022, 2021, 2020, 2019, 2018, 2017, 2016 by perlancar <perlancar@cpan.org>. This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself. =head1 BUGS Please report any bugs or feature requests on the bugtracker website L<https://rt.cpan.org/Public/Dist/Display.html?Name=App-CSVUtils> When submitting a bug or request, please include a test-file or a patch to an existing test-file that illustrates the bug or desired feature. =cut