Implement ID3 decision tree algorithm for classification. Data Mining and Business Intelligence GTU 2170715

             

Code:

import java.util.*;

import java.io.*;

import java.lang.*;

public class ID3

{

public static String[][]

in={{"RID","Age","Income","Student","Credit_rating","buys_computers"},

{"1","youth","high","no","fair","no"},

{"2","youth","high","no","excellent","no"},

{"3","middle_aged","high","no","fair","yes"},

{"4","senior","medium","no","fair","yes"},

{"5","senior","low","yes","fair","yes"},

{"6","se    nior","low","yes","excellent","no"},

{"7","middle_aged","low","yes","excellent","yes"},

{"8","youth","medium","no","fair","no"},

{"9","youth","low","yes","fair","yes"},

{"10","senior","medium","yes","fair","yes"},

{"11","youth","medium","yes","excellent","yes"},

{"12","middle_aged","medium","no","excellent","yes"},

{"13","middle_aged","high","yes","fair","yes"},

{"14","senior","medium","no","excellent","no"},

};

public static void main(String args[])throws IOException

{

for(int i=0;i<1;i++)

{

for(int j=0;j<6;j++)

{

if(j==1)

System.out.print(in[i][j]+"\t \t");

else

System.out.print(in[i][j]+"\t");

}

System.out.println();

}

System.out.println("-----------------------------------------------------------------------");

for(int i=1;i<15;i++)

{

for(int j=0;j<6;j++)

{

if(j==4)

{

if(i==1 || i==3 || i==4 || i==5 || i==8 || i==9 ||i==10 ||i==13)

System.out.print(in[i][j]+"\t \t");

else

System.out.print(in[i][j]+"\t");

    

}

else if(j==1)

{

if(i==3 || i==7 || i==12 || i==13)

System.out.print(in[i][j]+"\t");

else

System.out.print(in[i][j]+"\t \t");

}

else

System.out.print(in[i][j]+"\t");

    

}

System.out.println();

}

System.out.println("--------------------------------------------------------------------");

System.out.println();

Scanner sc=new Scanner(System.in);

System.out.println("Labeled Class is buys_computers");

int c=0,n=0,p=0;

int len=(in.length)-1;

double D=0.0,D1=0.0,G=0.0;

System.out.println("L : "+len);

for(int j=0;j<6;j++)

{

if(in[0][j   ].equals("buys_computers"))

{

p=j;

break;

}

}

for(int i=1;i<15;i++)

{

if(in[i][p].equals("no"))

n++;

else

c++;

    

}

System.out.println("No : "+n);

System.out.println("Yes :"+c);

D=info_D(n,c,len);

System.out.println("D : "+D);

System.out.println("");

String es;

do

{

System.out.println("Choose column name for which u want to calculate

expected information : \n 1. Age \n 2. Income \n 3. Student \n 4. Credit_rating \n

5. Exit \n ");

es=sc.nextLine();

switch(es)

{

case "Age" : D1=info_age(es,len);

System.out.println("\n D1 : "+D1);

G=D-D1;

System.out.println("\n Gain : "+G+"\n \n ");

break;      

case "Income" : D1=info_income(es,len);

System.out.println("\n D1 : "+D1);

G=D-D1;

System.out.println("\n Gain : "+G+"\n \n ");

break;

case "Student" : D1=info_student(es,len);

System.out.println("\n D1 : "+D1);

G=D-D1;

System.out.println("\n Gain : "+G+"\n \n ");

break;

case "Credit_rating" : D1=info_credit_rating(es,len);

System.out.println("\n D1 : "+D1);

G=D-D1;

System.out.println("\n Gain : "+G+"\n \n ");

break;

}

}while(!es.equals("Exit"));

System.out.println("\n Decision Tree : ");

System.out.println("\n age - youth - student - no - no ");

System.out.println("\n age - youth - student - yes - yes ");

System.out.println("\n age - middle_aged - yes : ");

System.out.println("\n age - senior - Credit_rating - fair - yes ");

System.out.println("\n age - senior - Credit_rating - excellent - no ");

}

public static double log_base2(int x, int base, int l)

{

if(x==0)

return 0;

else if(l==0)

return (double)(Math.log(x) / Math.log(base));

else

return (double)((Math.log(x) / Math.log(base))-(Math.log(l) /

Math.log(base)));

}

public static double info_D(int n,int c,int l)

{

double D;

D = (-((double)n/l)*(log_base2(n,2,l))) + (-((double)c/l)*(log_base2(c,2,l)));

return D;

}

public static double info_age(String es,int l)

{

int n=0,c=0,n1=0,c1=0,p=0,p1=0,n2=0,c2=0;

double D;

for(int j=0;j<6;j++)

{

if(in[0][j].equals(es))

{

p=j;

break;

}

}

for(int j=0;j<15;j++)

{

if(in[0][j].equals("buys_computers"))

{

p1=j;

break;

}

}

int y=0,s=0,m=0;

for(int i=1;i<15;i++)

{

if(in[i][p].equals("youth"))

{

y++;

if(in[i][p1].equals("no"))

n++;

else

c++;

}

else if(in[i][p].equals("senior"))

{

s++;

if(in[i][p1].equals("no"))

n1++;

else

c1++;

}

else

{

m++;

if(in[i][p1].equals("no"))

n2++;

else

c2++;

}

}

System.out.println("\n \n For Age : \n ");

System.out.println("Youth : "+y+" Yes : "+c+" No : "+n);

System.out.println("Senior : "+s+" Yes : "+c1+" No : "+n1);

System.out.println("Middle-aged : "+m+" Yes : "+c2+" No : "+n2);

D=((((double)y/l)*info_D(n,c,y))+(((double)s/l)*info_D(n1,c1,s))+(((doubl

e)m/l)*info_D(n2,c2,m)));

return D;

}

public static double info_income(String es,int l)

{

int n=0,c=0,n1=0,c1=0,p=0,p1=0,n2=0,c2=0;

double D;

for(int j=0;j<6;j++)

{

if(in[0][j].equals(es))

{

p=j;

break;

}

}

for(int j=0;j<15;j++)

{

if(in[0][j].equals("buys_computers"))

{

p1=j;

break;

}

}

int h=0,lo=0,m=0;

for(int i=1;i<15;i++)

{

if(in[i][p].equals("high"))

{

h++;

if(in[i][p1].equals("no"))

n++;

else

c++;

}

else if(in[i][p].equals("low"))

{

lo++;

if(in[i][p1].equals("no"))

n1++;

else

c1++;

}

else

{

m++;

if(in[i][p1].equals("no"))

n2++;

else

c2++;

}

}

System.out.println("\n \n For Income : \n ");

System.out.println("High : "+h+" Yes : "+c+" No : "+n);

System.out.println("Low : "+lo+" Yes : "+c1+" No : "+n1);

System.out.println("Medium : "+m+" Yes : "+c2+" No : "+n2);

D=((((double)h/l)*info_D(n,c,h))+(((double)lo/l)*info_D(n1,c1,lo))+(((double)m

/l)*info_D(n2,c2,m)));

return D;

}

public static double info_student(String es,int l)

{

int n=0,c=0,n1=0,c1=0,p=0,p1=0,n2=0,c2=0;

double D;

for(int j=0;j<6;j++)

{

if(in[0][j].equals(es))

{

p=j;

break;

}

}

for(int j=0;j<15;j++)

{

if(in[0][j].equals("buys_computers"))

{

p1=j;

break;

}

}

int y=0,n0=0;

for(int i=1;i<15;i++)

{

if(in[i][p].equals("yes"))

{

y++;

if(in[i][p1].equals("no"))

n++;

else

c++;

}

else

{

n0++;

if(in[i][p1].equals("no"))

n1++;

else

c1++;

}

}

System.out.println("\n \n For Student : \n ");

System.out.println("Yes : "+y+" Yes : "+c+" No : "+n);

System.out.println("No : "+n0+" Yes : "+c1+" No : "+n1);

D=((((double)y/l)*info_D(n,c,y))+(((double)n0/l)*info_D(n1,c1,n0)));

return D;

}

public static double info_credit_rating(String es,int l)

{

int n=0,c=0,n1=0,c1=0,p=0,p1=0,n2=0,c2=0;

double D;

for(int j=0;j<6;j++)

{

if(in[0][j].equals(es))

{

p=j;

break;

}

}

for(int j=0;j<15;j++)

{

if(in[0][j].equals("buys_computers"))

{

p1=j;

break;      

}

}

int f=0,e=0;

for(int i=1;i<15;i++)

{

if(in[i][p   ].equals("fair"))

{

f++;

if(in[i][p1].equals("no"))

n++;

else

c++;

    

}

else

{

e++;

if(in[i][p1].equals("no"))

n1++;

else

c1++;

    

}

}

System.out.println("\n \n For Credit_rating : \n ");

System.out.println("Fair : "+f+" Yes : "+c+" No : "+n);

System.out.println("Excellent : "+e+" Yes : "+c1+" No : "+n1);

D=((((double)f/l)*info_D(n,c,f))+(((double)e/l)*info_D(n1,c1,e)));

return D;

}