In a dataset, there is always a chance that we do not need some attributes hence we use feature selection.

We will be dropping ‘date’ and ‘instant’ columns from our dataset.

#Feature Selectiondf = df.drop(columns=['dteday','instant'])

Normalizing the data using sklearn package in python

# Normalizing the datafrom sklearn import preprocessingx=df.drop(['cnt'],axis=1)y=df['cnt']x = preprocessing.normalize(x)

And dividing into training and testing sets to be ready for any model or algorithm to work.

#Splitting the datasetfrom sklearn.model_selection import train_test_splitx_train, x_test, y_train, y_test = train_test_split(x, y, test_size = 0.3, random_state = 0)

Regression Techniques

Now we will be applying different regression techniques using the existing libraries in python.

Linear Regression

linear regression is a linear approach to modeling the relationship between a scalar response and one or more explanatory variables.

#Linear Regressionfrom sklearn.linear_model import LinearRegressionfrom sklearn.metrics import mean_squared_errorfrom sklearn.metrics import mean_absolute_errorfrom sklearn.metrics import r2_scorelinearRegressor = LinearRegression()linearRegressor.fit(x_train, y_train)y_predicted = linearRegressor.predict(x_test)mse = mean_squared_error(y_test, y_predicted)r = r2_score(y_test, y_predicted)mae = mean_absolute_error(y_test,y_predicted)print("Mean Squared Error:",mse)print("R score:",r)print("Mean Absolute Error:",mae)

Polynomial Regression

Polynomial regression is a form of regression analysis in which the relationship between the independent variable x and the dependent variable y is modeled as an nth degree polynomial in x.

from sklearn.preprocessing import PolynomialFeaturespolynomial_features= PolynomialFeatures(degree=2)x_poly = polynomial_features.fit_transform(x_train)x_poly_test = polynomial_features.fit_transform(x_test)model = LinearRegression()model.fit(x_poly, y_train)y_predicted_p = model.predict(x_poly_test)mse = mean_squared_error(y_test, y_predicted_p)r = r2_score(y_test, y_predicted_p)mae = mean_absolute_error(y_test,y_predicted_p)print("Mean Squared Error:",mse)print("R score:",r)print("Mean Absolute Error:",mae)

Decision Tree

Decision tree builds regression or classification models in the form of a tree structure. It breaks down a dataset into smaller and smaller subsets while at the same time an associated decision tree is incrementally developed.

# Decision Treefrom sklearn.tree import DecisionTreeRegressorregressor = DecisionTreeRegressor(random_state = 0)regressor.fit(x_train, y_train)y_predicted_d = regressor.predict(x_test)mse = mean_squared_error(y_test, y_predicted_d)r = r2_score(y_test, y_predicted_d)mae = mean_absolute_error(y_test,y_predicted_d)print("Mean Squared Error:",mse)print("R score:",r)print("Mean Absolute Error:",mae)

Random Forest

Random forests or random decision forests are an ensemble learning method for classification, regression and other tasks that operates by constructing a multitude of decision trees at training time and outputting the class that is the mode of the classes (classification) or mean prediction (regression).

# Random Forestfrom sklearn.ensemble import RandomForestClassifierrf = RandomForestClassifier()rf.fit(x_train,y_train);y_predicted_r = rf.predict(x_test)mse = mean_squared_error(y_test, y_predicted_r)r = r2_score(y_test, y_predicted_r)mae = mean_absolute_error(y_test,y_predicted_r)print("Mean Squared Error:",mse)print("R score:",r)print("Mean Absolute Error:",mae)

Rather than trying each and every algorithm separately, we will try a new method and display it using pretty tables

Code:

from sklearn.linear_model import Lasso, ElasticNet, Ridge, SGDRegressorfrom sklearn.svm import SVR, NuSVRfrom sklearn.ensemble import BaggingRegressor, RandomForestRegressorfrom sklearn.neighbors import KNeighborsClassifierfrom sklearn.cluster import KMeansimport matplotlib.pyplot as pltfrom prettytable import PrettyTablefrom sklearn.ensemble import RandomForestClassifierfrom sklearn.ensemble import GradientBoostingClassifiertable = PrettyTable()table.field_names = ["Model", "Mean Squared Error", "R² score","Mean Absolute Error"]models = [LinearRegression(),DecisionTreeRegressor(random_state = 0),RandomForestRegressor( random_state=0, n_estimators=300),SGDRegressor(max_iter=1000, tol=1e-3),Lasso(alpha=0.1),ElasticNet(random_state=0),Ridge(alpha=.5),BaggingRegressor(),BaggingRegressor(KNeighborsClassifier(), max_samples=0.5, max_features=0.5),]for model in models:model.fit(x_train, y_train)y_res = model.predict(x_test)mse = mean_squared_error(y_test, y_res)score = model.score(x_test, y_test)mae = mean_absolute_error(y_test,y_res)table.add_row([type(model).__name__, format(mse, '.2f'), format(score, '.2f'),format(mae, '.2f')])print(table)

CONCLUSION

From the above output, we see that ElasticNet works best for our dataset.

And if you want to get the whole code for the algorithms tested above, you can find it here 🙂

Blog by:

Naman Bansal

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