Class: Mikon::DataFrame

Inherits:
Object
  • Object
show all
Defined in:
lib/mikon/core/dataframe.rb,
lib/mikon/plot.rb,
lib/mikon/pivot.rb

Overview

The main data structure in Mikon gem. DataFrame consists of labels(column name), index(row name), and labels.

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(source, options = {}) ⇒ DataFrame

Returns a new instance of DataFrame.



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# File 'lib/mikon/core/dataframe.rb', line 12

def initialize(source, options={})
  options = {
    name: SecureRandom.uuid(),
    index: nil,
    labels: nil
  }.merge(options)

  case
  when source.is_a?(Array)
    case
    when source.length == 0
      @data = [DArray.new([])]
    when source.all? {|el| el.is_a?(Mikon::Series)}
      raise "NotImplementedError" + source.to_s

    when source.all? {|el| el.is_a?(Mikon::DArray)}
      @data = source

    when source.all? {|el| el.is_a?(Mikon::Row)}
      @labels = source.first.labels
      @index = source.map{|row| row.index}
      @data = source.map{|row| row.to_hash.values}.transpose.map do |arr|
        Mikon::DArray.new(arr)
      end

    when source.all? {|el| el.is_a?(Hash)}
      @labels = source.first.keys
      @data = source.map{|hash| hash.values}.transpose.map do |arr|
        Mikon::DArray.new(arr)
      end

    when source.all? {|el| el.is_a?(Array)}
      @data = source.map do |arr|
        Mikon::DArray.new(arr)
      end

    else raise "Non-acceptable Arguments Error"
    end

  when source.is_a?(Hash)
    case
    when source.values.all? {|val| val.is_a?(Array)}
      @labels = source.keys
      @data = source.values.map do |arr|
        Mikon::DArray.new(arr)
      end
    when source.all? {|arr| arr[1].is_a?(Series)}
    else raise "Non-acceptable Arguments Error"
    end

  else raise "Non-acceptable Arguments Error"
  end

  @labels = options[:labels] unless options[:labels].nil?
  @name = options[:name]

  unless (index = options[:index]).nil?
    if index.is_a?(Symbol)
      raise "labels should be set" if @labels.nil?
      pos = @labels.index(index)
      raise "Thre is no column named" + index.to_s if pos.nil?
      name = @labels.delete(index)
      @index = @data.delete(@data[pos])
    elsif index.is_a?(Array)
      @index = index
    else
      raise "Invalid index type"
    end
  end

  _check_if_valid
end

Instance Attribute Details

#index ⇒ Object (readonly)

Returns the value of attribute index.



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# File 'lib/mikon/core/dataframe.rb', line 366

def index
  @index
end

#labels ⇒ Object (readonly)

Returns the value of attribute labels.



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# File 'lib/mikon/core/dataframe.rb', line 366

def labels
  @labels
end

#name ⇒ Object (readonly)

Returns the value of attribute name.



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# File 'lib/mikon/core/dataframe.rb', line 366

def name
  @name
end

Class Method Details

.from_csv(path, options = {}) {|csv| ... } ⇒ Object

Create Mikon::DataFrame from a csv/tsv file

Parameters:

  • path (String) —

    path to csv

  • options (defaults to: {}) —

    :col_sep [String] string to separate by :headers [Array] headers

Yields:

  • (csv)

Raises:

  • (ArgumentError) 


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# File 'lib/mikon/core/dataframe.rb', line 113

def self.from_csv(path, options={})
  csv_options = {
    :col_sep => ',',
    :headers => true,
    :converters => :numeric,
    :header_converters => :symbol,
  }

  options = csv_options.merge(options)
  raise ArgumentError, "options[:hearders] should be set" if options[:headers] == false
  options.delete(:header_converters) if options[:headers].is_a?(Array)

  csv = CSV.readlines(path, "r", options)
  yield csv if block_given?

  hash = {}
  csv.by_col.each {|label, arr| hash[label] = arr}
  csv_options.keys.each{|key| options.delete(key)}

  self.new(hash, options)
end

Instance Method Details

#[](arg) ⇒ Object

Accessor for column and rows

Examples:

df = DataFrame.new({a: [1, 2, 3], b: [2, 3, 4]})
df[0..1].to_json #-> {a: [1, 2], b: [2, 3]}
df[:a] #-> <Mikon::Series>


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# File 'lib/mikon/core/dataframe.rb', line 140

def [](arg)
  case
  when arg.is_a?(Range)
    index = @index.select{|i| arg.include?(i)}
    Mikon::DataFrame.new(index.map{|i| self.row(i)}, {index: index})

  when arg.is_a?(Symbol)
    self.column(arg)
  end
end

#_check_if_valid ⇒ Object 



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# File 'lib/mikon/core/dataframe.rb', line 85

def _check_if_valid
  # All array should should have the same length
  length = @data.map{|darr| darr.length}.max
  @data.each{|darr| darr.expand(length) if darr.length < length}

  # DataFrame should have index object
  @index = (0..(length-1)).to_a if @index.nil?
  raise "index should have the same length as arrays" if @index.length != length

  # Labels should be an instance of Symbol
  if @labels.nil?
    @labels = @data.map.with_index{|darr, i| i.to_s.to_sym}
  elsif @labels.any?{|label| !label.is_a?(Symbol)}
    @labels = @labels.map{|label| label.to_sym}
  end
end

#all?(&block) ⇒ Boolean

Mikon::Row DSL

Returns:

  • (Boolean) 


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# File 'lib/mikon/core/dataframe.rb', line 246

def all?(&block)
  self.each_row {|row| return false unless row.instance_eval(&block)}
  true
end

#any?(&block) ⇒ Boolean

Mikon::Row DSL

Returns:

  • (Boolean) 


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# File 'lib/mikon/core/dataframe.rb', line 252

def any?(&block)
  self.each_row {|row| return true if row.instance_eval(&block)}
  false
end

#column(label) ⇒ Object

Access column with its name



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# File 'lib/mikon/core/dataframe.rb', line 152

def column(label)
  pos = @labels.index(label)
  raise "There is no column named " + label if pos.nil?
  Mikon::Series.new(label, @data[pos], index: @index)
end

#delete(label) ⇒ Object

Delete column



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# File 'lib/mikon/core/dataframe.rb', line 351

def delete(label)
  pos = @labels.index(label)
  raise "there is no column named " + label.to_s if pos.nil?
  @labels.delete_at(pos)
  @data.delete_at(pos)
end

#dup ⇒ Object 



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# File 'lib/mikon/core/dataframe.rb', line 358

def dup
  Mikon::DataFrame.new(@data.map{|darr| darr.dup}, {index: @index, label: @labels})
end

#dup_only_valid ⇒ Object 



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# File 'lib/mikon/core/dataframe.rb', line 362

def dup_only_valid
  self.dup
end

#each(&block) ⇒ Object

Iterate rows using Mikon::Row DSL



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# File 'lib/mikon/core/dataframe.rb', line 225

def each(&block)
  return self.to_enum(:each) unless block_given?
  self.each_row do |row|
    row.instance_eval(&block)
  end
  self
end

#each_row(&block) ⇒ Object

Iterate row



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# File 'lib/mikon/core/dataframe.rb', line 334

def each_row(&block)
  return self.to_enum(:each_row) unless block_given?
  @index.each.with_index do |el, i|
    row_arr = @data.map{|darr| darr[i]}
    row = Mikon::Row.new(@labels, row_arr, @index[i])
    block.call(row)
  end
end

#fillna(value = 0) ⇒ Object

Replace NaN with specified value (destructive)

Parameters:

  • value (Float|Fixnum) (defaults to: 0) —

    new value to replace NaN



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# File 'lib/mikon/core/dataframe.rb', line 345

def fillna(value=0)
  @data.each {|darr| darr.fillna(value)}
  self
end

#head(num) ⇒ Object

same as head of Linux



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# File 'lib/mikon/core/dataframe.rb', line 159

def head(num)
  self[0..(num-1)]
end

#insert_column(*args, &block) ⇒ Object

Insert column using Mikon::Row DSL or raw Array

Examples:

df = Mikon::DataFrame.new({a: [1,2,3], b: [2,3,4]})
df.insert_column(:c){a + b}.to_json #-> {a: [1,2,3], b: [2,3,4], c: [3,5,7]}
df.insert_column(:d, [1, 2, 3]).to_json #-> {a: [1,2,3], b: [2,3,4], c: [3,5,7], d: [1,2,3]}
df.insert_column((df[:d]*2).name(:e)) #-> {a: [1,2,3], b: [2,3,4], c: [3,5,7], d: [1,2,3], e: [2,4,6]

Parameters:

  • Symbol (label) —

    the name of new column (optional)

  • the (Array|Series|DArray) —

    content of new column (optional)



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# File 'lib/mikon/core/dataframe.rb', line 290

def insert_column(*args, &block)
  if block_given?
    rows = []
    name = args[0]
    self.each_row do |row|
      val = row.instance_eval(&block)
      row[name] = val
      rows.push(row)
    end
    @data = rows.map{|row| row.to_hash.values}.transpose.map do |arr|
      Mikon::DArray.new(arr)
    end
    @labels = rows.first.labels
  else
    if args[0].is_a?(Symbol)
      name = args[0]
      case
      when args[1].is_a?(Mikon::DArray)
        @data.push(args[1])
      when args[1].is_a?(Mikon::Series)
        @data.push(args[1].to_darr)
      when args[1].is_a?(Array)
        @data.push(Mikon::DArray.new(args[1]))
      else
        raise ArgumentError
      end
    elsif args[0].is_a?(Mikon::Series)
      @data.push(args[0].to_darr)
      name = args[0].name
    end
    @labels.push(name)
  end
  _check_if_valid
  return self
end

#length ⇒ Object

return the length of columns



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# File 'lib/mikon/core/dataframe.rb', line 103

def length
  @data.first.length
end

#map(&block) ⇒ Object Also known as: collect

Iterate rows using Mikon::Row DSL and return new Mikon::Series



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# File 'lib/mikon/core/dataframe.rb', line 234

def map(&block)
  return self.to_enum(:map) unless block_given?
  arr = []
  self.each_row do |row|
    arr.push(row.instance_eval(&block))
  end
  Mikon::Series.new(:new_series, arr, index: @index.clone)
end

#pivot(args = {}) ⇒ Object

Experimental Implementation. DO NOT USE THIS METHOD

Raises:

  • (ArgumentError) 


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# File 'lib/mikon/pivot.rb', line 5

def pivot(args={})
  args = {
    column: nil,
    row: nil,
    value: nil,
    fill_value: Float::NAN
  }.merge(args)

  raise ArgumentError unless [:column, :row, :value].all?{|sym| args[sym].is_a?(Symbol)}

  column = self[args[:column]].factors
  index = self[args[:row]].factors

  source = column.reduce({}) do |memo, label|
    arr = []
    df = self.select{|row| row[args[:column]] == label}
    index.each do |i|
      unless df.any?{|row| row[args[:row]] == i}
        arr.push(args[:fill_value])
      else
        column = df.select{|row| row[args[:row]] == i}[args[:value]]
        arr.push(column.to_a[0])
      end
    end
    memo[label] = arr
    memo
  end

  Mikon::DataFrame.new(source, index: index)
end

#plot(args = {}) ⇒ Object 



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# File 'lib/mikon/plot.rb', line 24

def plot(args={})
  args = {
    :type => :line,
    :x => nil,
    :y => nil,
    :fill_by => nil,
    :color => nil
  }.merge(args)

  plot = Nyaplot::Plot.new
  plot.x_label("")
  plot.y_label("")

  unless args[:color].nil?
    colors = Nyaplot::Colors.send(args[:color]).to_a
  else
    colors = Nyaplot::Colors.qual.to_a
  end

  case args[:type]
  when :line
    @data.each.with_index do |darr, i|
      line = plot.add(:line, @index, darr.to_a)
      line.color(colors.pop)
      line.title(@labels[i])
    end
    plot.legend(true)

  when :box
    plot.add_with_df(self, :box, *@labels)

  when :scatter
    sc = plot.add_with_df(self, :scatter, args[:x], args[:y])
    sc.color(colors)
    sc.fill_by(args[:fill_by]) unless args[:fill_by].nil?
    plot.x_label(args[:x])
    plot.y_label(args[:y])
  end

  plot
end

#row(index) ⇒ Object

Access row using index



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# File 'lib/mikon/core/dataframe.rb', line 327

def row(index)
  pos = @index.index(index)
  arr = @data.map{|column| column[pos]}
  Mikon::Row.new(@labels, arr, index)
end

#select(&block) ⇒ Object Also known as: filter

Select rows using Mikon::Row DSL and create new DataFrame

Examples:

df = Mikon::DataFrame.new({a: [1,2,3], b: [2,3,4]})
df.select{a%2==0}[:a].to_a #-> [2]


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# File 'lib/mikon/core/dataframe.rb', line 210

def select(&block)
  return self.to_enum(:select) unless block_given?
  rows = []
  i = 0
  self.each_row do |row|
    if row.instance_eval(&block)
      rows.push(row)
    end
  end
  Mikon::DataFrame.new(rows)
end

#sort(label, ascending = true) ⇒ Object

Sort by label

Parameters:

  • label (Symbol) —

    column name to sort by

  • ascending (Bool) (defaults to: true) —

    default true



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# File 'lib/mikon/core/dataframe.rb', line 273

def sort(label, ascending=true)
  i = @labels.index(label)
  raise "No column named" + label.to_s if i.nil?
  order = @data[i].sorted_indices
  order.reverse! unless ascending
  self.sort_by.with_index{|val, i| order.index(i)}
end

#sort_by(ascending = true, &block) ⇒ Object

Sort using Mikon::Row DSL

Parameters:

  • ascending (Bool) (defaults to: true) —

    default true



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# File 'lib/mikon/core/dataframe.rb', line 260

def sort_by(ascending=true, &block)
  return self.to_enum(:sort_by) unless block_given?
  order = self.map(&block).to_darr.sorted_indices
  order.reverse! unless ascending
  data = @data.map{|darr| darr.sort_by.with_index{|val, i| order.index(i)}}
  index = @index.sort_by.with_index{|val, i| order.index(i)}
  Mikon::DataFrame.new(data, {index: index, labels: @labels})
end

#tail(num) ⇒ Object

same as tail of Linux



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# File 'lib/mikon/core/dataframe.rb', line 164

def tail(num)
  last = self.length-1
  self[(last-num+1)..last]
end

#to_html(threshold = 50) ⇒ Object

IRuby notebook automatically call this method



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# File 'lib/mikon/core/dataframe.rb', line 179

def to_html(threshold=50)
  html = "<html><table><tr><td></td>"
  html += @labels.map{|label| "<th>" + label.to_s +  "</th>"}.join
  html += "</tr>"
  self.each_row.with_index do |row, pos|
    next if pos > threshold && pos != self.length-1
    html += "<tr><th>" + @index[pos].to_s + "</th>"
    html += @labels.map{|label| "<td>" + row[label].to_s + "</td>"}.join
    html += "</tr>"
    html += "<tr><th>...</th>" + "<td>...</td>"*@labels.length + "</tr>" if pos == threshold
  end
  html += "</table>"
end

#to_json(*args) ⇒ Object

Compartible with Nyaplot::DataFrame.to_json



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# File 'lib/mikon/core/dataframe.rb', line 170

def to_json(*args)
  rows = []
  self.each_row do |row|
    rows.push(row.to_hash)
  end
  rows.to_json
end

#to_s(threshold = 50) ⇒ Object 



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# File 'lib/mikon/core/dataframe.rb', line 193

def to_s(threshold=50)
  arr = []
  self.each_row.with_index do |row, pos|
    next nil if pos > threshold && pos != self.length-1
    arr.push({"" => @index[pos]}.merge(row.to_hash))
    if pos == threshold
        arr.push(@labels.reduce({"" => "..."}){|memo, label| memo[label] = "..."; memo})
    end
  end
  Formatador.display_table(arr.select{|el| !(el.nil?)})
end