Rover_summary_example.md

Rover summary method example

This is a experimental code and usage of Rover::DataFrame#summary of Ruby.

This method is not implemented in official release.

Rover_summary_example_1.ipynb

rover_summary_prepend.rb

module My
  module RoverVectorPrepender
    
    def mean
      @data.cast_to(Numo::DFloat).mean(nan: true)
    end

    def median
      @data.cast_to(Numo::DFloat).median(nan: true)
    end

    def std
      @data.cast_to(Numo::DFloat).stddev(nan: true)
    end

    def var
      @data.cast_to(Numo::DFloat).var(nan: true)
    end
  end

  module RoverDataFramePrepender

    # Show statistical summary of self
    # - Returns DataFrame
    # - Make stats for numeric columns only
    # - 1st column header indicates [n of rows, n of numeric columns] 
    # - Int type columns are casted to Float64 in mean, std, var (by Vector)
    # - NaNs are ignored using (nan: true) option in Numo
    #   - counts also show non-NaN counts
    def summary
      num_keys = self.keys.select {|key| self[key].numeric?}
      nrow, _ = self.shape
      key0 = :"[#{nrow},#{num_keys.size}]"
      round = 6

      hash = {key0 => num_keys}
      hash["count"] = num_keys.map {|k| self[k].missing.to_numo.count_false }
      hash["mean"]  = num_keys.map {|k| self[k].mean.round(round) }
      hash["std"]   = num_keys.map {|k| self[k].std.round(round) }
      hash["min"]   = num_keys.map {|k| self[k].min }
      hash["25%"]   = num_keys.map {|k| self[k].percentile(25).round(round) }
      hash["50%"]   = num_keys.map {|k| self[k].percentile(50).round(round) }
      hash["75%"]   = num_keys.map {|k| self[k].percentile(75).round(round) }
      hash["max"]   = num_keys.map {|k| self[k].max }
      
      Rover::DataFrame.new(hash)
    end

    # This method may be abandoned
    # - My first implementation
    # - Counts sould be Int but casted to Float
    def summary_T
      num_keys = self.keys.select {|key| self[key].numeric?}
      # use key of 1st column to show n_rows and n_of_numeric_columns
      nrow, _ = self.shape
      key0 = :"[#{nrow},#{num_keys.size}]"
      round = 6

      ary = [] <<
        num_keys.each_with_object({key0 => "count"}) {|k, h| h[k] = self[k].missing.to_numo.count_false } <<
        num_keys.each_with_object({key0 => "mean"})  {|k, h| h[k] = self[k].mean.round(round) } <<
        num_keys.each_with_object({key0 => "std"})   {|k, h| h[k] = self[k].std.round(round) } <<
        num_keys.each_with_object({key0 => "min"})   {|k, h| h[k] = self[k].min } <<
        num_keys.each_with_object({key0 => "25%"})   {|k, h| h[k] = self[k].percentile(25).round(round) } <<
        num_keys.each_with_object({key0 => "50%"})   {|k, h| h[k] = self[k].percentile(50).round(round) } <<
        num_keys.each_with_object({key0 => "75%"})   {|k, h| h[k] = self[k].percentile(75).round(round) } <<
        num_keys.each_with_object({key0 => "max"})   {|k, h| h[k] = self[k].max }

      Rover::DataFrame.new(ary)
    end
  end
end

Rover::Vector.prepend My::RoverVectorPrepender
Rover::DataFrame.prepend My::RoverDataFramePrepender