String row = reader.nextLine(); String[] chunks = row.split(","); Integer.valueOf(chunk);

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

@@ -0,0 +1,116 @@
+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
+
+
+
+
+
+===================================================================
+
+
+
+
+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
+
+
+
+
+