Module: DaruLite::DataFrame::Convertible

Included in:
DaruLite::DataFrame
Defined in:
lib/daru_lite/data_frame/convertible.rb

Instance Method Summary collapse

Instance Method Details

#create_sql(table, charset = 'UTF8') ⇒ Object

Create a sql, basen on a given Dataset

Arguments

  • table - String specifying name of the table that will created in SQL.

  • charset - Character set. Default is “UTF8”.

Examples:


ds = DaruLite::DataFrame.new({
 :id   => DaruLite::Vector.new([1,2,3,4,5]),
 :name => DaruLite::Vector.new(%w{Alex Peter Susan Mary John})
})
ds.create_sql('names')
 #=>"CREATE TABLE names (id INTEGER,\n name VARCHAR (255)) CHARACTER SET=UTF8;"


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# File 'lib/daru_lite/data_frame/convertible.rb', line 20

def create_sql(table, charset = 'UTF8')
  sql    = "CREATE TABLE #{table} ("
  fields = vectors.to_a.collect do |f|
    v = self[f]
    "#{f} #{v.db_type}"
  end

  sql + fields.join(",\n ") + ") CHARACTER SET=#{charset};"
end

#to_a ⇒ Object

Converts the DataFrame into an array of hashes where key is vector name and value is the corresponding element. The 0th index of the array contains the array of hashes while the 1th index contains the indexes of each row of the dataframe. Each element in the index array corresponds to its row in the array of hashes, which has the same index.



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# File 'lib/daru_lite/data_frame/convertible.rb', line 47

def to_a
  [each_row.map(&:to_h), @index.to_a]
end

#to_df ⇒ self

Returns the dataframe. This can be convenient when the user does not know whether the object is a vector or a dataframe.

Returns:

  • (self) —

    the dataframe



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# File 'lib/daru_lite/data_frame/convertible.rb', line 33

def to_df
  self
end

#to_h ⇒ Object

Converts DataFrame to a hash (explicit) with keys as vector names and values as the corresponding vectors.



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# File 'lib/daru_lite/data_frame/convertible.rb', line 63

def to_h
  @vectors
    .each_with_index
    .map { |vec_name, idx| [vec_name, @data[idx]] }.to_h
end

#to_html(threshold = DaruLite.max_rows) ⇒ Object

Convert to html for IRuby.



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# File 'lib/daru_lite/data_frame/convertible.rb', line 70

def to_html(threshold = DaruLite.max_rows)
  table_thead = to_html_thead
  table_tbody = to_html_tbody(threshold)
  path = if index.is_a?(MultiIndex)
           File.expand_path('../iruby/templates/dataframe_mi.html.erb', __dir__)
         else
           File.expand_path('../iruby/templates/dataframe.html.erb', __dir__)
         end
  ERB.new(File.read(path).strip).result(binding)
end

#to_html_tbody(threshold = DaruLite.max_rows) ⇒ Object 



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# File 'lib/daru_lite/data_frame/convertible.rb', line 91

def to_html_tbody(threshold = DaruLite.max_rows)
  threshold ||= @size
  table_tbody_path =
    if index.is_a?(MultiIndex)
      File.expand_path('../iruby/templates/dataframe_mi_tbody.html.erb', __dir__)
    else
      File.expand_path('../iruby/templates/dataframe_tbody.html.erb', __dir__)
    end
  ERB.new(File.read(table_tbody_path).strip).result(binding)
end

#to_html_thead ⇒ Object 



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# File 'lib/daru_lite/data_frame/convertible.rb', line 81

def to_html_thead
  table_thead_path =
    if index.is_a?(MultiIndex)
      File.expand_path('../iruby/templates/dataframe_mi_thead.html.erb', __dir__)
    else
      File.expand_path('../iruby/templates/dataframe_thead.html.erb', __dir__)
    end
  ERB.new(File.read(table_thead_path).strip).result(binding)
end

#to_json(no_index = true) ⇒ Object

Convert to json. If no_index is false then the index will NOT be included in the JSON thus created.



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# File 'lib/daru_lite/data_frame/convertible.rb', line 53

def to_json(no_index = true)
  if no_index
    to_a[0].to_json
  else
    to_a.to_json
  end
end

#to_matrix ⇒ Object

Convert all vectors of type :numeric into a Matrix.



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# File 'lib/daru_lite/data_frame/convertible.rb', line 38

def to_matrix
  Matrix.columns each_vector.select(&:numeric?).map(&:to_a)
end

#to_s ⇒ Object 



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# File 'lib/daru_lite/data_frame/convertible.rb', line 102

def to_s
  "#<#{self.class}#{": #{@name}" if @name}(#{nrows}x#{ncols})>"
end