从文件读取整数并将值存储到数组

Question

I have a file, lets say data.txt which contains data in the following format

1 12
2 84
3 82
9 82
3 1
3 2

The first number indicates what index of the array the second number should be added to. I am having trouble working this out... I wanted to create a method that parses through the .txt file and adds the values to the appropriate index then returns the array with all the numbers added up.

Answer 1

Try this.

Code

Scanner sc = new Scanner(new File("data.txt"));
int[] arr = new int[10];
while(sc.hasNextLine()) {

    String line[] = sc.nextLine().split("\\s");
    int ele = Integer.parseInt(line[1]);
    int index = Integer.parseInt(line[0]);
    arr[index] = ele;

}
int sum = 0;
for(int i = 0; i<arr.length; i++) {
    sum += arr[i];
    System.out.print(arr[i] + "\t");
}
System.out.println("\nSum : " + sum);
return sum;

Output

0   12  84  2   0   0   0   0   0   82
Sum : 180

Here sc.nextLine().split("\\\\s"); reads each line and spits that line by space into an array line[] . line[0] will have index and line[1] will have element. It will be in form of String. It can be converted to int by Integer.parseInt() . ele store the element and index stores the index of that element after converting to int .

Some index are not specified in the file so its value will be 0 .

Some of the index in your code has repeated so that values will be overwritten.

Answer 2

I took the text file as 1 12 2 84 3 86 4 17 5 18 9 10

which contains 12 numbers.

Please dont give repeated index

public class FileArray {

public static void main(String[] args) throws FileNotFoundException {
    FileReader file=new FileReader("data.txt");
    int[] array=new int[12]; //i took size of array as total numbers in text file,
    int i=0;
    try{
    Scanner sc=new Scanner(file);
    while(sc.hasNext()){
        array[i]=sc.nextInt();
        i++;
    }
    sc.close();
    }
    catch(Exception e)
    {
        System.out.println(e);
    }
    System.out.println(Arrays.toString(array));
    int size=(array.length)/2;
    int[] index=new int[size];
    int j=0;
    for(int k=0;k<array.length;k++)
    {
        if(k%2==0)
        {
        index[j]=array[k];
        j++;
        }
    }
    System.out.println(Arrays.toString(index));
    int[] res=new int[10];
    int m=1;
    for(int l=0;l<index.length;l++)
    {
        res[index[l]]=array[m];
        m+=2;
    }
    System.out.println(Arrays.toString(res));
    }
    }

output: [1, 12, 2, 84, 3, 86, 4, 17, 5, 18, 9, 10]

[1, 2, 3, 4, 5, 9]

[0, 12, 84, 86, 17, 18, 0, 0, 0, 10]