如何从 txt 文件行读取并打印字符串和整数数组

Question

我正在从文本文件中读取由用户输入定义的特定行 if(nameLine.contains(inputFileName)){ 我正在尝试从该行打印一组名称和一组数字。谁能帮我解决这个问题？我必须创建 2 种不同的方法还是可以在 main 中全部完成？我只知道如何在 while loop 的一个代码中使用一个 Array，但我不确定如何将它们组合在一起。感谢您的帮助！

My code is not finished, but this is how it looks so far

public static void main(String[] args) throws IOException {

    Scanner in = new Scanner(System.in);
    System.out.print("Enter the State name: ");
    String inputFileName = in.next();
    String names = "pplnames17.txt";

    List<String> namearr = new ArrayList<String>();

    File namesFile = new File(names);
    Scanner stateSearch = new Scanner (namesFile);

    //print title
    String line0 = Files.readAllLines(Paths.get("pplnames17.txt")).get(0);
    System.out.printf("%s in %s", line0, inputFileName);

    while(stateSearch.hasNextLine()){
        String nameLine = stateSearch.nextLine();
        if(nameLine.contains(inputFileName)){
            System.out.printf("\n%s",nameLine);
        }
    }

This is a partial of my Array code for String, which I had it after a while loop

    while(stateSearch.hasNextLine()){
    namearr.add(stateSearch.nextLine());
}
String[] arr = namearr.toArray(new String [0]);
System.out.println(arr);

Answer 1

虽然这不是最好的解决方案，但您可以 upon/tidy 建立一个潜在的解决方案。

基本上，读入您的文件，遍历每一行，如果该行包含用户输入，则拆分该行上的每个 string，检查是文本还是数字，然后添加到相关数组。

public static void main(String[] args) throws FileNotFoundException {
        List<String> nameArr = new ArrayList<>();
        List<Double> intArr = new ArrayList<>();
        System.out.print("Enter the State name: ");
        Scanner in = new Scanner(System.in);
        String inputFileName = in.next();

        Scanner sc = new Scanner(new File("pplnames17.txt"));

        while (sc.hasNextLine()) {
            String nameLine = sc.nextLine();
            if (nameLine.contains(inputFileName)) {
                String[] inputs = nameLine.split(" ");
                for (String input : inputs) {
                    if (isNumeric(input)) {
                        intArr.add(Double.parseDouble(input));
                    } else {
                        nameArr.add(input);
                    }
                }
            }
        }
        if (!nameArr.isEmpty()) {
            System.out.println(nameArr);
        } else {
            System.out.println("No names found");
        }
        if (!intArr.isEmpty()) {
            System.out.println(intArr);
        } else {
            System.out.println("No numbers found");
        }
    }

    public static boolean isNumeric(String str) {
        try {
            double d = Double.parseDouble(str);
        } catch (NumberFormatException e) {
            return false;
        }
        return true;
    }

我测试了一下，我的文本文件是这样的：

abc def ghi 12 55 jkl mno pqr

joe jack mary 1 2 james 4

paul jim kim bob 45 othername

bill yu will gill 455 Paulo

mary 的用户输入给出了输出：

[joe, jack, mary, james]

[1.0, 2.0, 4.0]

如何从 txt 文件行读取并打印字符串和整数数组

How to read from txt file line and print arrays of strings and integers

java

arrays

string

int

readfile