java - 从数据文件中的一行整数中查找最大值和最小值

Question

我正在尝试从数据文件中查找一行文本的最大值和最小值。尽管此数据文件中有大量文本行。

数据

-99 1 2 3 4 5 6 7 8 9 10 12345
10 9 8 7 6 5 4 3 2 1 -99
10 20 30 40 50 -11818 40 30 20 10
32767
255 255
9 10 -88 100 -555 1000
10 10 10 11 456
-111 1 2 3 9 11 20 30
9 8 7 6 5 4 3 2 0 -2 -989
12 15 18 21 23 1000
250 19 17 15 13 11 10 9 6 3 2 1 -455
9 10 -8 10000 -5000 1000

我尝试过将线条转换为数组，这让我有所收获。

这是我的代码

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

// It is called "Average". Don't mind that.
public class Average 
{
    public static void main(String[] args) throws IOException
    {
        Scanner file = new Scanner(new File("average.dat"));


        String[] array = null;

        while(file.hasNextLine())
        {
        //Storing the ints from the data file into an array.
        String line = file.nextLine();
        String[] str = line.split("\\s+");
        array = new String[str.length];
        for (int i = 0; i < str.length; i++){
            array[i] = (str[i]);
        }
        System.out.println("Max:" + Average.getMax(array));
        System.out.println("Min:" + Average.getMin(array));
        System.out.println();
        }

    }
    //Simple way of getting max value. Nabbed it off google.
    public static String getMax(String[] inputArray)
    { 
        String maxValue = inputArray[0]; 
        for(int i=1;i < inputArray.length;i++){ 
          if(inputArray[i].compareTo(maxValue)>0){ 
             maxValue = inputArray[i]; 
          } 
        } 
        return maxValue; 
     }
    //Simple way of getting min value. Took off google as well.
    public static String getMin(String[] inputArray){ 
        String minValue = inputArray[0]; 
        for(int i=1;i<inputArray.length;i++){ 
          if(inputArray[i].compareTo(minValue)<0){ 
            minValue = inputArray[i]; 
          } 
        } 
        return minValue; 
      } 
}

这是我的输出

Max:9
Min:-99

Max:9
Min:-99

Max:50
Min:-11818

Max:32767
Min:32767

Max:255
Min:255

Max:9
Min:-555

Max:456
Min:10

Max:9
Min:-111

Max:9
Min:-2

Max:23
Min:1000

Max:9
Min:-455

Max:9
Min:-5000

如您所见，最小值是正确的。但是，最大值不是吗？它无缘无故地给我9分，我不知道为什么。您可能会问“为什么不直接将数组设为 int[] 而不是 String[]？”我不知道如何将数据文件中的整数复制到整数数组中。我只知道如何使用字符串数组来做到这一点。有谁知道正确的方法吗？

Answer 1

带有注释和解释的紧凑解决方案:

public static void main(String[] args) {

    // Create an input stream
    try (Stream<String> stream = Files.lines(Paths.get("average.dat"))) {

        // Get each line from the stream
        stream.forEach(line -> {

            // Cut the line into peaces
            String[] numbers = line.split(" ");

            // Create a list of integers from the pieces
            List<Integer> integers = Arrays.stream(numbers).map(Integer::parseInt).collect(Collectors.toList());

            // Calculate max
            System.out.println("Max:" + integers.stream().flatMapToInt(IntStream::of).max().orElseThrow());

            // Calculate min
            System.out.println("Min:" + integers.stream().flatMapToInt(IntStream::of).min().orElseThrow());

            // Ouput a new line
            System.out.println();
        });
    } catch (IOException e) {
        e.printStackTrace();
    }