将每行从整数列表转换为整数数组? [英] Converting each line from a list of integers into an array of integers?

问题描述

我是Java新手，如果其中任何一个不清楚，我们深表歉意-我想将四位数整数列表转换为整数数组列表-即，如果我有一个4567的整数，我想将其转换为四个独立整数的数组[4、5、6、7].因此，我想将列表的每一行/索引转换为它自己的数组(而不是将整个列表转换为数组).我目前正在读取一个包含四位数整数的文件(每个文件都在新行上)并将其添加到列表中，然后该列表返回该列表-有关如何编码以使其返回整数列表的任何想法而不是数组?

I'm new to Java, so apologies if any of this is unclear - I want to convert a list of four-digit integers into a list of integer arrays - i.e if I have an integer that is 4567, I want to convert that into an array of four separate integers [4, 5, 6, 7]. So I want to convert each line/index of the list into it's own array (rather than converting the entire list into an array). I'm currently reading a file that has four-digit integers (each on a new line) and adding them to a list, which is then returning that list - any ideas on how could I code it so that it returns a list of integer arrays instead?

    public List <Integer> loadGuesses (String fileName){

    List<Integer> loadGuessList = new ArrayList<>();

    try (BufferedReader reader = new BufferedReader(new FileReader(fileName))) {
        String line;
        while ((line = reader.readLine()) != null) {
            loadGuessList.add(Integer.parseInt(line));
        }
    } catch (FileNotFoundException f){
        System.out.println("File not found - please re-enter with correct file name.");
        getPlayerFile();
    } catch (IOException e){
        System.out.println("Incorrect file name - Please re-enter with correct file name.");
        getPlayerFile();
    }
    return loadGuessList;

}

推荐答案

将loadGuessList的类型更改为List<int[]>.

读取字符串后，您可以遍历字符并将每个字符转换为整数.

After reading the string, you can iterate through the characters and convert each to an int.

  List<int[]> loadGuessList = new ArrayList<>();

  while ((line = reader.readLine()) != null) {
    int [] digits = new int[4];
    for (int i = 0; i < line.length(); i++) { //Assuming line.length() will be 4
        digits[i] = line.charAt(i) - '0';
    }
    loadGuessList.add(digits);
}

参考: 如何在Java中将char转换为int?

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