Lokesh Sharma lokeshh

(taken from GSOC proposal)

...

contrast_interact: This is there to code interaction terms. In a dataframe with columns ‘a’ and ‘b’, ‘a:b’ is an interaction term. Again we need to code this term to produce some number of variables. But in this case the coding is somewhat different. I’ll explain with an example how to code ‘a:b’ and one can generalize the behavior. Let’s say column ‘a’ has m categories and ‘b’ has n categories. Now if ‘a’ has been mentioned in our regression expression, then we will code the column ‘b’ with n-1 variables and similarly if ‘b’ has been mentioned in the regression expression, then we will code column ‘a’ with m-1 variables. And if ‘a’ hasn’t been mentioned in our regression expression then ‘b’ will be coded with n variables and similarly if ‘a’ hasn’t been mentioned in our regression expression then ‘b’ will be coded with m variables.

Here’s a general rule to follow when we have more than two way interaction. Say we have ‘a: b:c’ and we need to decide whether to code ‘a’ w

Implement Formula language and categorical variable support in Statsample::Regression

Below is how Statsample performs regression.

def self.multiple(ds,y_var, opts=Hash.new)
  missing_data= (opts[:missing_data].nil? ) ? :listwise : opts.delete(:missing_data)
  if missing_data==:pairwise
     Statsample::Regression::Multiple::RubyEngine.new(ds,y_var, opts)
 else

class Formula
  Formula class will be used by Statsample to parse a regression formula.
  It consist of two data members.
  attr_accessor :left_terms # This will store all the left terms. For example: ['y'] in case of 'y ~ a*b'
  attr_accessor :right_terms # This will store all the right terms. For example: ['a', 'b', ['a', 'b']]
  # in case of 'y ~ a*b'
  
  It will expose 'from_formula' function to the statsample to parse formulas
  For example to parse the formula 'y ~ a*b', Statsample will call the following function

Daru

Pull Requests [Merged]:

Dataframe#sort speed up: Improve DataFrame sort function performance. Add functionality to handle nils and make function optimal for advance as well for beginner's use.
Tune up sort: Improve Vector sort function performance. Add cabability to handle nils.
Insert nyaplot link in README: Insert hyperlink for nyaplot in README file.
Refactor indexing: Improve the structure of Index class to better accomodate other Index subclasses with it's use with Vector and DataFrame
Correct some spelling mistakes: Correct some spelling mistakes.
Set name of first column: Solved first column named as nil bug.

Below is a list of online MOOC's I've successfully completed:

Edx Courses:

Massive Open Online Courses (MOOC's) by MIT:

Introduction to Computer Sciend and Programming using Python [MITx - 6.00.1x] Certificate
Introduction to Computational Thinking and Data Science [MITx - 6.00.2x] Certificate

	=begin
	Usage:
	To convert expressions involving '*', '/' and brackets to expressions only involving '+' and ':' use #from_formula
	>> Formula.new.from_formula '(a+b):(c+d)'
	=> "a:c+a:d+b:c+b:d"
	>> Formula.new.from_formula 'abc*d'
	=> "a+b+a:b+c+a:c+b:c+a:b:c+d+a:d+b:d+a:b:d+c:d+a:c:d+b:c:d+a:b:c:d"
	=end

	class Formula

	module CategoricalData
	def size
	20
	end
	end

	class Vector
	def initialize type = nil
	self.extend(CategoricalData) if type == :category
	end

	(venv) lokeshh:~/workspace/sciruby-notebooks (update_notebooks) $ gem uninstall statsample

	You have requested to uninstall the gem:
	statsample-2.0.1

	sciruby-full-0.2.7 depends on statsample (~> 2.0)
	statsample-bivariate-extension-1.2.0 depends on statsample (~> 2.0)
	statsample-glm-0.2.1 depends on statsample (~> 2.0)
	If you remove this gem, these dependencies will not be met.
	Continue with Uninstall? [yN] y

	<html lang='en'>
	<head>
	<title>Nyaplot</title>
	<script src="http://cdnjs.cloudflare.com/ajax/libs/require.js/2.1.14/require.min.js"></script>
	<script>if(window['d3'] === undefined \|\|
	window['Nyaplot'] === undefined){
	var path = {"d3":"https://cdnjs.cloudflare.com/ajax/libs/d3/3.5.5/d3.min","downloadable":"http://cdn.rawgit.com/domitry/d3-downloadable/master/d3-downloadable"};

	NoMethodError: undefined method `keys' for nil:NilClass
	/var/lib/gems/2.1.0/gems/daru-0.1.2/lib/daru/index.rb:122:in `key'
	/var/lib/gems/2.1.0/gems/gnuplotrb-0.3.3/lib/gnuplotrb/staff/dataset.rb:252:in `get_daru_columns'
	/var/lib/gems/2.1.0/gems/gnuplotrb-0.3.3/lib/gnuplotrb/staff/dataset.rb:281:in `init_daru_vector'
	/var/lib/gems/2.1.0/gems/gnuplotrb-0.3.3/lib/gnuplotrb/staff/dataset.rb:67:in `initialize'
	/var/lib/gems/2.1.0/gems/gnuplotrb-0.3.3/lib/gnuplotrb/plot.rb:273:in `new'
	/var/lib/gems/2.1.0/gems/gnuplotrb-0.3.3/lib/gnuplotrb/plot.rb:273:in `dataset_from_any'
	/var/lib/gems/2.1.0/gems/gnuplotrb-0.3.3/lib/gnuplotrb/plot.rb:289:in `block in parse_datasets_array'
	/var/lib/gems/2.1.0/gems/gnuplotrb-0.3.3/lib/gnuplotrb/plot.rb:289:in `map'
	/var/lib/gems/2.1.0/gems/gnuplotrb-0.3.3/lib/gnuplotrb/plot.rb:289:in `parse_datasets_array'