1)conversion.java
package com.decorator;

public interface conversion
{
public String convert(String str);

}

2)Characters.java
package com.decorator;

public class Characters implements conversion
{

@Override
public String convert(String str) {
	// TODO Auto-generated method stub
	return str.toLowerCase();
}

}

3)DecoratorMainDemo.java
package com.decorator;

public class DecoratorMaindemo
{
public static void main(String args[])
{
String s1 = "ABC";
System.out.println("Uppercase is :--> "+s1);
Characters c1 = new Characters();

	System.out.println("Lowercase is :---> "+c1.convert(s1));
}

}

import pandas as pd
df=pd.read_csv('Downloads/housing_data.csv')
print(df.head(10))

X = df['area (in cm)'].values
Y = df['price in lakhs'].values
from sklearn.linear_model import LinearRegression
from sklearn.metrics import mean_squared_error
n=len(X)
X = X.reshape((n, 1))
reg = LinearRegression()
reg = reg.fit(X, Y)
Y_pred = reg.predict(X)
print(Y_pred)

Calculating R2 Score

r2_score = reg.score(X, Y)
print(r2_score)

import pandas as pd
df=pd.read_csv('Downloads/housing_data.csv')
print(df.head(10))

n=len(df)
print(n)

import numpy as np
X = df['area (in cm)'].values
Y = df['price in lakhs'].values
mean_x = np.mean(X)
mean_y=np.mean(Y)
print(mean_x)
print(mean_y)

numerator = 0
denominator = 0
for i in range(len(df)):
numerator += (X[i] - mean_x) * (Y[i] - mean_y)
denominator += (X[i] - mean_x) ** 2
m = numerator / denominator
c = mean_y - (m * mean_x)

Print coefficients

print(m, c)

import matplotlib.pyplot as plt

Plotting Values and Regression Line

max_x = np.max(X) + 100
min_x = np.min(X) - 100

Calculating line values x and y

x = np.linspace(min_x, max_x, 1000)
y = c + m * x

Ploting Line

plt.plot(x, y, color='blue', label='Regression Line')

Ploting Scatter Points

plt.scatter(X, Y, c='red', label='Scatter Plot')

plt.xlabel('Area (in cm)')
plt.ylabel('Price in lakhs')
plt.legend()
plt.show()

ss_t = 0
ss_r = 0
for i in range(len(df)):
y_pred = c + m * X[i]
ss_t += (Y[i] - mean_y) ** 2
ss_r += (Y[i] - y_pred) ** 2
r2 = 1 - (ss_r/ss_t)
print(r2)

var str = "Hello World without built-in module";
var res = str.toUpperCase();
console.log(res);

// var uc = require('upper-case');
// var str = "Hello World using built-in module";
// res=uc.upperCase(str);
// console.log(res);