techscientist / visualize_ml

Python package to visualize some processes involved in Machine learning.

visualize_ML

visualize_ML is a python package made to visualize some of the steps involved while dealing with a Machine Learning problem. It is build on libraries like matplotlib for visualization and sklean,scipy for statistical computations.

Table of content:

• Requirements
• Install
• Let's code
  • explore module
  • relation module
• Contribute
• Tasks To Do
• Licence
• Copyright

Requirement

• python 2.x or python 3.x

Install

Install it using pip

pip install visualize_ML

Let's Code

While dealing with a Machine Learning problem some of the initial steps involved are data exploration,analysis followed by feature selection.Below are the modules for these tasks.

1) Data Exploration

At this stage, we explore variables one by one using Uni-variate Analysis which depends on whether the variable type is categorical or continuous .To deal with this we have the explore module.

>>> explore module

visualize_ML.explore.plot(data_input,categorical_name=[],drop=[],PLOT_COLUMNS_SIZE=4,bin_size=20,
bar_width=0.2,wspace=0.5,hspace=0.8)

Continuous Variables : In case of continous variables it plots the Histogram for every variable and gives descriptive statistics for them.

Categorical Variables : In case on categorical variables with 2 or more classes it plots the Bar chart for every variable and gives descriptive statistics for them.

Parameters	Type	Description
data_input	Dataframe	This is the input Dataframe with all data.(Right now the input can be only be a dataframe input.)
categorical_name	list (default=[ ])	Names of all categorical variable columns with more than 2 classes, to distinguish them with the continuous variablesEmply list implies that there are no categorical features with more than 2 classes.
drop	list default=[ ]	Names of columns to be dropped.
PLOT_COLUMNS_SIZE	int (default=4)	Number of plots to display vertically in the display window.The row size is adjusted accordingly.
bin_size	int (default="auto")	Number of bins for the histogram displayed in the categorical vs categorical category.
wspace	float32 (default = 0.5)	Horizontal padding between subplot on the display window.
hspace	float32 (default = 0.8)	Vertical padding between subplot on the display window.

Code Snippet

/* The data set is taken from famous Titanic data(Kaggle)*/

import pandas as pd
from visualize_ML import explore
df = pd.read_csv("dataset/train.csv")
explore.plot(df,["Survived","Pclass","Sex","SibSp","Ticket","Embarked"],drop=["PassengerId","Name"])

see the dataset

Note: While plotting all the rows with NaN values and columns with Character values are removed only numeric data is plotted.

2) Feature Selection

This is one of the challenging task to deal with for a ML task.Here we have to do Bi-variate Analysis to find out the relationship between two variables. Here, we look for association and disassociation between variables at a pre-defined significance level.

relation module helps in visualizing the analysis done on various combination of variables and see relation between them.

>>> relation module

visualize_ML.relation.plot(df,"Sex",["Survived","Pclass","Sex","SibSp","Ticket","Embarked"],drop=["PassengerId","Name"],bin_size=10)

Continuous vs Continuous variables: To do the Bi-variate analysis scatter plots are made as their pattern indicates the relationship between variables. To indicates the strength of relationship amongst them we use Correlation between them.

The graph displays the correlation coefficient along with other information.

Correlation = Covariance(X,Y) / SQRT( Var(X)*Var(Y))

• -1: perfect negative linear correlation
• +1:perfect positive linear correlation and
• 0: No correlation

Categorical vs Categorical variables: Stacked Column Charts are made to visualize the relation.Chi square test is used to derive the statistical significance of relationship between the variables. It returns probability for the computed chi-square distribution with the degree of freedom. For more information on Chi Test see this

Probability of 0: It indicates that both categorical variable are dependent

Probability of 1: It shows that both variables are independent.

The graph displays the p_value along with other information. If it is leass than 0.05 it states that the variables are dependent.

Categorical vs Continuous variables: To explore the relation between categorical and continuous variables,box plots re drawn at each level of categorical variables. If levels are small in number, it will not show the statistical significance. ANOVA test is used to derive the statistical significance of relationship between the variables.

The graph displays the p_value along with other information. If it is leass than 0.05 it states that the variables are dependent.

For more information on ANOVA test see this

Parameters	Type	Description
data_input	Dataframe	This is the input Dataframe with all data.(Right now the input can be only be a dataframe input.)
target_name	String	The name of the target column.
categorical_name	list (default=[ ])	Names of all categorical variable columns with more than 2 classes, to distinguish them with the continuous variablesEmply list implies that there are no categorical features with more than 2 classes.
drop	list default=[ ]	Names of columns to be dropped.
PLOT_COLUMNS_SIZE	int (default=4)	Number of plots to display vertically in the display window.The row size is adjusted accordingly.
bin_size	int (default="auto")	Number of bins for the histogram displayed in the categorical vs categorical category.
wspace	float32 (default = 0.5)	Horizontal padding between subplot on the display window.
hspace	float32 (default = 0.8)	Vertical padding between subplot on the display window.

Code Snippet

/* The data set is taken from famous Titanic data(Kaggle)*/
import pandas as pd
from visualize_ML import relation
df = pd.read_csv("dataset/train.csv")
relation.plot(df,"Survived",["Survived","Pclass","Sex","SibSp","Ticket","Embarked"],drop=["PassengerId","Name"],bin_size=10)

see the dataset

Note: While plotting all the rows with NaN values and columns with Non numeric values are removed only numeric data is plotted.Only categorical taget variable with string values are allowed.

Contribute

If you want to contribute and add new feature feel free to send Pull request here

This project is still under development so to report any bugs or request new features, head over to the Issues page

Tasks To Do

• Make input compatible with other formats like Numpy.

• Visualize best fit lines and decision boundaries for various models to make Parameter Tuning task easy.

  and many others!

Licence

Licensed under The MIT License (MIT).

Copyright

ayush1997(c) 2016