Week 3: Objects, files and exceptions/17a Handling file contents

nextLine() - returns String
valueOf() - Integer OR Double



===================================================================


import java.util.Arrays;

public class Example {
    public static void main(String[] args){
        String str = "first,second,third";
        String[] chunks = str.split(",");


        //print array - [first, second, third]
        System.out.println(Arrays.toString(chunks));
        //print string elements
        for (String chunk : chunks) {
            System.out.println(chunk);
        }


        String sentence ="This is a sentence with many words";
        String[] words = sentence.split(" ");
        System.out.println(Arrays.toString(words));
        for (String word : words) {
            System.out.println(word);
        }
    }
}

Program outputs:
[first, second, third]
first
second
third
[This, is, a, sentence, with, many, words]
This
is
a
sentence
with
many
words





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eg
luvut/numbers.csv
1,4,3,5,2,4,5,2
4,5,11,2,4,2,5,4,3
6,7,5,2,3,3,2,4,6
8,7,4,5,4,3,3,2,1
0,0,2,4,2,0,2,5,3






reads the file
decomposes each line into chunks, 
converts the chunks to integers and 
finally calculates the sum of the numbers:


import java.io.FileNotFoundException;
import java.io.File;
import java.util.Scanner;

public class Example {
    public static void main(String[] args){
        File file = new File("luvut.csv");
        
        // read the file
        try(Scanner reader = new Scanner(file)) {
            int sum = 0;
            while (reader.hasNextLine()) {

                // process line by line
                String row = reader.nextLine();
                // split into an array of number strings
                String[] chunks = row.split(",");

                // parse each number string as Integer
                for (String chunk : chunks) {
                    int num = Integer.valueOf(chunk);
                    sum += num;
                }
            }
            
            System.out.println("Sum of the numbers: " + sum);
        }  
        catch (FileNotFoundException e) {
            System.out.println("Error: " + e.getMessage());
        }
    }
}


Program outputs:
Sum of the numbers: 159