Adds support for Excelx (xlsx) Exporter

CONTRIBUTING.md

@@ -39,7 +39,7 @@ Please proceed with a Pull Request only after you're assigned. It'd be sad if yo
 
 4. Add any gem dependencies required for the Format Importer to the `:optional` group of the Gemfile.
 
-5. Add code and YARD documentation to `lib/daru/io/importers/format.rb`, consistent with other IO modules.
+5. Add code and YARD documentation to `lib/daru/io/importers/format.rb`, consistent with other IO modules. Update the `README.md` if required.
 
 6. Add tests to `spec/daru/io/importers/format_spec.rb`. Add any `.format` files required for importer in `spec/fixtures/format/` directory.
 

Gemfile

@@ -12,6 +12,7 @@ group :optional do
   gem 'redis'
   gem 'roo', '~> 2.7.0'
   gem 'rsruby'
+  gem 'rubyXL'
   gem 'snappy'
   gem 'spreadsheet', '~> 1.1.1'
   gem 'sqlite3'

README.md

@@ -20,7 +20,7 @@ While supporting various IO modules, daru-io also provides an easier way of addi
 
 - [Installation](#installation)
 - *[Importers](#importers): [ActiveRecord](#activerecord-importer), [Avro](#avro-importer), [CSV](#csv-importer), [Excel](#excel-importer), [Excelx](#excelx-importer), [HTML](#html-importer), [JSON](#json-importer), [Mongo](#mongo-importer), [Plaintext](#plaintext-importer), [RData](#rdata-importer), [RDS](#rds-importer), [Redis](#redis-importer), [SQL](#sql-importer)*
-- *[Exporters](#exporters): [Avro](#avro-exporter), [CSV](#csv-exporter), [Excel](#excel-exporter), [JSON](#json-exporter), [RData](#rdata-exporter), [RDS](#rds-exporter), [SQL](#sql-exporter)*
+- *[Exporters](#exporters): [Avro](#avro-exporter), [CSV](#csv-exporter), [Excel](#excel-exporter), [Excelx](#excelx-exporter), [JSON](#json-exporter), [RData](#rdata-exporter), [RDS](#rds-exporter), [SQL](#sql-exporter)*
 - [Creating your own IO modules](#creating-your-own-io-modules)
 - [Contributing](#contributing)
 - [License](#license)
@@ -458,6 +458,28 @@ Exports a **Daru::DataFrame** into a **.xls** file.
     df.write_excel('path/to/file.xls', header: {color: :red, weight: :bold}, data: {color: :blue }, index: false)
     ```
 
+### Excelx Exporter
+
+[(Go to Table of Contents)](#table-of-contents)
+
+Exports a **Daru::DataFrame** into a **.xlsx** file.
+
+- **Docs**: [rubydoc.info](http://www.rubydoc.info/github/athityakumar/daru-io/master/Daru/IO/Exporters/Excelx)
+- **Gem Dependencies**: `rubyXL` gem
+- **Usage**:
+    ```ruby
+    #! Partially require just Excelx Exporter
+    require 'daru/io/exporters/excelx'
+
+    #! Usage from Daru::IO
+    string = Daru::IO::Exporters::Excelx.new(df, index: false).to_s
+    Daru::IO::Exporters::Excelx.new(df, index: false).write('path/to/file.xlsx')
+
+    #! Usage from Daru::DataFrame
+    string = df.to_excelx_string(index: false)
+    df.write_excel('path/to/file.xlsx', index: false)
+    ```
+
 ### JSON Exporter
 
 [(Go to Table of Contents)](#table-of-contents)

daru-io.gemspec

@@ -33,5 +33,6 @@ Gem::Specification.new do |spec|
   spec.add_development_dependency 'simplecov'
   spec.add_development_dependency 'webmock'
   spec.add_development_dependency 'yard'
+
   spec.add_development_dependency 'guard-rspec' if RUBY_VERSION >= '2.2.5'
 end

lib/daru/io/exporters/avro.rb

@@ -78,6 +78,7 @@ def write(path)
           @writer.close
 
           File.open(path, 'w') { |file| file.write(@buffer.string) }
+          true
         end
 
         private

lib/daru/io/exporters/base.rb

@@ -41,8 +41,8 @@ def initialize(dataframe)
         #
         #   instance = Daru::IO::Exporters::Format.new(opts)
         #   instance.to_s #! same as df.to_format_string(opts)
-        def to_s
-          tempfile = Tempfile.new('tempfile')
+        def to_s(file_extension: '')
+          tempfile = Tempfile.new(['filename', file_extension])
           path     = tempfile.path
           write(path)
 

lib/daru/io/exporters/csv.rb

@@ -80,6 +80,7 @@ def write(path)
             contents.each { |content| csv << content }
             csv.close
           end
+          true
         end
 
         private

lib/daru/io/exporters/excel.rb

@@ -62,7 +62,7 @@ def initialize(dataframe, header: true, data: true, index: true)
         # @return [String] A file-writable string
         #
         # @example Getting a file-writable string from Excel Exporter instance
-        #   simple_instance.to_s #! same as df.to_avro_string(schema)
+        #   simple_instance.to_s
         #
         #   #=> "\xD0\xCF\u0011\u0871\u001A\xE1\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000..."
         #
@@ -92,6 +92,7 @@ def write(path)
           end
 
           @book.write(path)
+          true
         end
 
         private

lib/daru/io/exporters/excelx.rb

@@ -0,0 +1,114 @@
+require 'daru/io/exporters/base'
+
+module Daru
+  module IO
+    module Exporters
+      # Excelx Exporter Class, that extends `to_excelx_string` and `write_excelx` methods to
+      # `Daru::DataFrame` instance variables
+      class Excelx < Base
+        Daru::DataFrame.register_io_module :to_excelx_string, self
+        Daru::DataFrame.register_io_module :write_excelx, self
+
+        # Initializes an Excelx Exporter instance.
+        #
+        # @param dataframe [Daru::DataFrame] A dataframe to export. Supports even dataframes
+        #   with multi-index.
+        # @param sheet [String] A sheet name, to export the dataframe into. Defaults to
+        #   'Sheet0'.
+        # @param header [Boolean] Defaults to true. When set to false or nil,
+        #   headers are not written.
+        # @param data [Boolean] Defaults to true. When set to false or nil,
+        #   data values are not written.
+        # @param index [Boolean] Defaults to true. When set to false or nil,
+        #   index values are not written
+        #
+        # @example Initializing an Excel Exporter instance
+        #   df = Daru::DataFrame.new([[1,2],[3,4]], order: [:a, :b])
+        #
+        #   #=> #<Daru::DataFrame(2x2)>
+        #   #      a   b
+        #   #  0   1   3
+        #   #  1   2   4
+        #
+        #   instance = Daru::IO::Exporters::Excelx.new(df)
+        def initialize(dataframe, sheet: 'Sheet0', header: true, data: true, index: true)
+          optional_gem 'rubyXL'
+
+          super(dataframe)
+          @data   = data
+          @index  = index
+          @sheet  = sheet
+          @header = header
+        end
+
+        # Exports an Excelx Exporter instance to a file-writable String.
+        #
+        # @return [String] A file-writable string
+        #
+        # @example Getting a file-writable string from Excelx Exporter instance
+        #   instance.to_s
+        #
+        #   #=> "PK\u0003\u0004\u0014\u0000\u0000\u0000\b\u0000X\xA5YK\u0018\x87\xFC\u0017..."
+        def to_s
+          super(file_extension: '.xlsx')
+        end
+
+        # Exports an Excelx Exporter instance to an xlsx file.
+        #
+        # @param path [String] Path of excelx file where the dataframe is to be saved
+        #
+        # @example Writing an Excelx Exporter instance to an xlsx file
+        #   instance.write('filename.xlsx')
+        def write(path)
+          @workbook = RubyXL::Workbook.new
+          @sheet    = @workbook.add_worksheet(@sheet)
+          process_offsets
+
+          write_row(@header ? 0 : 1, fetch_headers)
+
+          @dataframe.each_row_with_index.with_index do |(row, idx), i|
+            write_row(@row_offset+i, fetch_index(idx) + fetch_data(row))
+          end
+
+          @workbook.write(path)
+          true
+        end
+
+        private
+
+        def process_offsets
+          @row_offset   = @header ? 1 : 0
+          @col_offset   = 0 unless @index
+          @col_offset ||= @dataframe.index.is_a?(Daru::MultiIndex) ? @dataframe.index.width : 1
+        end
+
+        def fetch_headers
+          formatting([' '] * @col_offset + @dataframe.vectors.map(&:to_s), @header)
+        end
+
+        def fetch_index(idx)
+          formatting(idx, @index)
+        end
+
+        def fetch_data(row)
+          formatting(row, @data)
+        end
+
+        def formatting(idx, format)
+          return [] unless format
+
+          case idx
+          when Daru::Vector, Daru::MultiIndex, Array then idx.map(&:to_s)
+          else [idx.to_s]
+          end
+        end
+
+        def write_row(row_index, row_array)
+          row_array.each_with_index do |element, col_index|
+            @sheet.insert_cell(row_index, col_index, element.to_s)
+          end
+        end
+      end
+    end
+  end
+end

lib/daru/io/exporters/json.rb

@@ -487,6 +487,7 @@ def write(path)
           File.open(path, 'w') do |file|
             file.write(::JSON.send(@pretty ? :pretty_generate : :generate, to))
           end
+          true
         end
 
         private

lib/daru/io/exporters/r_data.rb

@@ -59,6 +59,7 @@ def write(path)
           end.flatten
           @statements << "save(#{@options.keys.map(&:to_s).join(', ')}, file='#{path}')"
           @statements.each { |statement| @instance.eval_R(statement) }
+          true
         end
       end
     end

lib/daru/io/exporters/rds.rb

@@ -53,6 +53,7 @@ def write(path)
           @statements  = process_statements(@r_variable, @dataframe)
           @statements << "saveRDS(#{@r_variable}, file='#{path}')"
           @statements.each { |statement| @instance.eval_R(statement) }
+          true
         end
 
         private

lib/daru/io/importers/excel.rb

@@ -10,9 +10,9 @@ class Excel < Base
         Daru::DataFrame.register_io_module :read_excel do |*args, &io_block|
           if args.first.end_with?('.xlsx')
             require 'daru/io/importers/excelx'
-            Daru::IO::Importers::Excelx.new(*args[1..-1], &io_block).read(*args[0])
+            Daru::IO::Importers::Excelx.new.read(*args[0]).call(*args[1..-1], &io_block)
           else
-            Daru::IO::Importers::Excel.new(*args[1..-1], &io_block).read(*args[0])
+            Daru::IO::Importers::Excel.new.read(*args[0]).call(*args[1..-1], &io_block)
           end
         end
 

lib/daru/io/link.rb

@@ -25,20 +25,22 @@ class << self
       #
       # #### Exporters
       #
-      # | `Daru::DataFrame` instance method | `Daru::IO::Exporters` class        |
-      # | --------------------------------- | -----------------------------------|
-      # | `Daru::DataFrame.to_avro_string`  | {Daru::IO::Exporters::Avro#to_s}   |
-      # | `Daru::DataFrame.write_avro`      | {Daru::IO::Exporters::Avro#write}  |
-      # | `Daru::DataFrame.to_csv_string`   | {Daru::IO::Exporters::CSV#to_s}    |
-      # | `Daru::DataFrame.write_csv`       | {Daru::IO::Exporters::CSV#write}   |
-      # | `Daru::DataFrame.to_excel_string` | {Daru::IO::Exporters::Excel#to_s}  |
-      # | `Daru::DataFrame.write_excel`     | {Daru::IO::Exporters::Excel#write} |
-      # | `Daru::DataFrame.to_json`         | {Daru::IO::Exporters::JSON#to}     |
-      # | `Daru::DataFrame.to_json_string`  | {Daru::IO::Exporters::JSON#to_s}   |
-      # | `Daru::DataFrame.write_json`      | {Daru::IO::Exporters::JSON#write}  |
-      # | `Daru::DataFrame.to_rds_string`   | {Daru::IO::Exporters::RDS#to_s}    |
-      # | `Daru::DataFrame.write_rds`       | {Daru::IO::Exporters::RDS#write}   |
-      # | `Daru::DataFrame.to_sql`          | {Daru::IO::Exporters::SQL#to}      |
+      # | `Daru::DataFrame` instance method  | `Daru::IO::Exporters` class         |
+      # | -----------------------------------| ------------------------------------|
+      # | `Daru::DataFrame.to_avro_string`   | {Daru::IO::Exporters::Avro#to_s}    |
+      # | `Daru::DataFrame.write_avro`       | {Daru::IO::Exporters::Avro#write}   |
+      # | `Daru::DataFrame.to_csv_string`    | {Daru::IO::Exporters::CSV#to_s}     |
+      # | `Daru::DataFrame.write_csv`        | {Daru::IO::Exporters::CSV#write}    |
+      # | `Daru::DataFrame.to_excel_string`  | {Daru::IO::Exporters::Excel#to_s}   |
+      # | `Daru::DataFrame.write_excel`      | {Daru::IO::Exporters::Excel#write}  |
+      # | `Daru::DataFrame.to_excelx_string` | {Daru::IO::Exporters::Excelx#to_s}  |
+      # | `Daru::DataFrame.write_excelx`     | {Daru::IO::Exporters::Excelx#write} |
+      # | `Daru::DataFrame.to_json`          | {Daru::IO::Exporters::JSON#to}      |
+      # | `Daru::DataFrame.to_json_string`   | {Daru::IO::Exporters::JSON#to_s}    |
+      # | `Daru::DataFrame.write_json`       | {Daru::IO::Exporters::JSON#write}   |
+      # | `Daru::DataFrame.to_rds_string`    | {Daru::IO::Exporters::RDS#to_s}     |
+      # | `Daru::DataFrame.write_rds`        | {Daru::IO::Exporters::RDS#write}    |
+      # | `Daru::DataFrame.to_sql`           | {Daru::IO::Exporters::SQL#to}       |
       #
       # @param function [Symbol] Functon name to be monkey-patched into +Daru::DataFrame+
       # @param instance [Class] The Daru-IO class to be linked to monkey-patched function
@@ -62,7 +64,7 @@ def register_exporter(function, instance)
           case function.to_s
           when /\Ato_.*_string\Z/ then instance.new(self, *args, &io_block).to_s
           when /\Ato_/            then instance.new(self, *args, &io_block).to
-          when /Awrite_/          then instance.new(self, *args[1..-1], &io_block).write(*args[0])
+          when /\Awrite_/         then instance.new(self, *args[1..-1], &io_block).write(*args[0])
           end
         end
       end

spec/daru/io/exporters/csv_spec.rb

@@ -8,7 +8,7 @@
   before { described_class.new(df, opts).write(tempfile.path) }
 
   context 'writes DataFrame to a CSV file' do
-    subject { Daru::DataFrame.rows content[1..-1].map { |x| x.map { |y| convert(y) } }, order: content[0] }
+    subject { Daru::DataFrame.rows(content[1..-1].map { |x| x.map { |y| convert(y) } }, order: content[0]) }
 
     let(:opts) { {} }
     let(:content) { CSV.read(tempfile.path) }

spec/daru/io/exporters/excel_spec.rb

@@ -2,7 +2,7 @@
   include_context 'exporter setup'
 
   let(:filename) { 'test_write.xls' }
-  let(:content)  { Spreadsheet.open tempfile.path }
+  let(:content)  { Spreadsheet.open(tempfile.path) }
   let(:opts)     { {header: {color: :blue}, data: {color: :red}, index: {color: :green}} }
 
   before { described_class.new(df, **opts).write(tempfile.path) }

spec/daru/io/exporters/excelx_spec.rb

@@ -0,0 +1,39 @@
+RSpec.describe Daru::IO::Exporters::Excelx do
+  include_context 'exporter setup'
+
+  let(:filename) { ['test_write', '.xlsx'] }
+  let(:content)  { Roo::Excelx.new(tempfile.path).sheet('Sheet0').to_a }
+
+  before { described_class.new(df, **opts).write(tempfile.path) }
+
+  context 'writes to excelx worksheet without index' do
+    subject { Daru::DataFrame.rows(content[1..-1].map { |x| x.map { |y| convert(y) } }, order: content[0]) }
+
+    let(:opts) { {index: false} }
+
+    it_behaves_like 'exact daru dataframe',
+      ncols: 4,
+      nrows: 5,
+      order: %w[a b c d],
+      data: [
+        [1,2,3,4,5],
+        [11,22,33,44,55],
+        ['a', 'g', 4, 5,'addadf'],
+        ['', 23, 4,'a','ff']
+      ]
+  end
+
+  context 'writes to excelx worksheet with multi-index' do
+    subject { content.map { |x| x.map { |y| convert(y) } } }
+
+    let(:df) do
+      Daru::DataFrame.new(
+        [[1,2],[3,4]],
+        order: %i[x y],
+        index: [%i[a b c], %i[d e f]]
+      )
+    end
+
+    it { is_expected.to eq([[' ', ' ', ' ', 'x', 'y'], ['a', 'b', 'c', 1, 3], ['d', 'e', 'f', 2, 4]]) }
+  end
+end

spec/spec_helper.rb

@@ -17,6 +17,7 @@
 require 'dbd/SQLite3'
 require 'active_record'
 require 'redis'
+require 'roo'
 require 'dbi'
 require 'jsonpath'
 require 'nokogiri'