Thread: Import CSV data into 2d array then compare each row

Hey Guys;

I have a CSV file that i need to compare each row with the rest to see if they are equal or not.
I knew how to create an array list but i dont know how to carry on to compare each row alone with the others to see if their is other equal to it-Knowing that the number of rows and colomns in the CSV file is unknown- and save the result in a Right/Wrong variable.

this is my code to create the arraylist:

List<List<String>> records=new ArrayList<>();
 
		try(BufferedReader br=new BufferedReader(new FileReader("D:\\traincpu.csv"))) {
			String line=br.readLine();      //To skip first line added readline()
			int count=0;                    //   to count row numbers
 
 
		  	while((line=br.readLine()) !=null) {
				String[] values =line.split(";");
				 count=count+1;     
				records.add(Arrays.asList(values));
 
			}
		  	int rowcont=0;
		 // 	while((line=br.readLine())!="\n") {
		  		rowcont++;
		  //	}

Hello Jim, Thank you for your fast reply.

Each row in the file represent an attribute for a point; that point is a data i need to give it a weight then calculate the euclidean distance between this CSV file and another file which contain test data.(Yes its Machine learning algorithm)

So,the String option i think is not good idea and the output of the values above: 1, 2, "three, four", five is

Exception in thread "main" java.io.IOException: number expected, read Token[three, four], line 18

Plz i need help since im not a programmer but i need to edit a code in weka application for my collage studies.

MYCT,MMIN,MMAX,CACH,CHMIN,CHMAX,class
240,512,2000,8,1,5,11
105,2000,4000,8,3,8,22

it may contain also string data not only numeric.

This is an example of 2 rows of the file
note that i already collected the data from another file and saved them as csv file as the original file contain text.

Thank you that is so helpful; but i still have a problem in importing unknown number of rows from a CSV file.


plz check the following:

public class array {
 
	public static void main(String[] args) {   
 
		//  String[] records==new ArrayList<>();   
 
		String fileName= "example.csv";
        File file= new File(fileName);
 
 
        try{
            Scanner inputStream= new Scanner(file);
            while(inputStream.hasNext()){
 
            String data= inputStream.next();
            String[] records = data.split(",");
            System.out.print(records[2]+ ",");
            }
            inputStream.close();
         } catch (Exception e) {                                                       
			 System.out.println(e.getMessage());                                      
			 System.exit(-1);   
    }
 
 
		  for (int i = 0; i < records.length - 1; i++) {                              // error: records cannot be resolved to a variable
			 int[] r1 = toIntArray(records[i]);                                     // error: records cannot be resolved to a variable     
			 inner:                                                                   
			 for (int k = i + 1; k < records.length; k++) {                     // error: records cannot be resolved to a variable                            
				int[] r2 = toIntArray(records[k]);                             // error: records cannot be resolved to a variable          
				if (r1.length == r2.length) {                                         
				   for (int r = 0; r < r1.length; r++) {                              
					  if (r1[r] != r2[r]) {                                           
						 continue inner;                                              
					  }                                                               
				   }                                                                  
				   System.out.println("row " + i + " equals to row " + k);            
				}                                                                     
			 }                                                                        
		  }                                                                           
		}   
 
 
		public static int[] toIntArray(String s) {                                     
		  String[] tokens = s.split(",");                                             
		  int[] temp = new int[tokens.length];                                        
		  try {                                                                       
			 for (int i = 0; i < tokens.length; i++) {                                
				temp[i] = Integer.parseInt(tokens[i]);                                
			 }                                                                        
		  }                                                                           
		  catch (Exception e) {                                                       
			 System.out.println(e.getMessage());                                      
			 System.exit(-1);                                                         
		  }                                                                           
		  return temp;                                                                
		}
 
}

I dont know how to call rows from the csv file after i saved the data into an array.


Regards