Question

我正在逐行读取文件，我需要按字母顺序对行进行排序，例如，在下面的示例中，它应按每个单词的首字母排序并输出。我坚持如何按字母顺序将每个单词的第一个字符排序，并保留每个单词前面的数字。任何帮助表示赞赏。预先感谢。

output: 567 cat
        123 dog

FILE2 = "123 dog\n567 cat\n";

String args[] = {"-a", "5", inputFile.getPath()};

String expected = 567 cat
                  123 dog

我尝试阅读行和排序，但是它首先根据数字排序。

if (arguments.equals("-a")) {                      
   List<String> lines = Files.readAllLines((Paths.get(filename)));

    List<String> matchedLines = lines.stream().sorted()
                                     .collect(Collectors.toList());

Answer 1

您可以执行以下操作（请注意，我没有在文件中放入任何内容，就像您已经做过的那样，很容易从文件中取出字符串）。以下代码假定您从文件中获取了字符串：

public static void main(String[] args) {
    //what we have got from file
    String text = "123 dog\n567 cat\n";
    //split text to substrings by new line
    String[] splitted = text.split("\n");
    // create treemap and sort it from greatest to lowest number
    Map<Integer, String> mapOfStrings = new TreeMap<Integer, String>().descendingMap();
    //put all substrings into our map, following assumes a form that first substring is a text and second substring is an integer
    for (int i = 0; i < splitted.length; i++) {
        mapOfStrings.put(Integer.valueOf(splitted[i].substring(0, splitted[i].indexOf(" "))), splitted[i].substring(splitted[i].indexOf(" "), splitted[i].length()));
    }
   //iterate thru map, for each entry in it print its key and value in single line
    for (Map.Entry<Integer, String> entry : mapOfStrings.entrySet()) {
        System.out.println(entry.getKey() + " " + entry.getValue());
    }
}

更新2：

如果您想按字母（从a到z）排序，则下面的代码就足够了：

 public static void main(String[] args) {
        String text = "123 dog\n567 cat\n4 zebra\n1983 tiger\n1 lion\n383 turtle";
        String[] splitted = text.split("\n");
        System.out.println(Arrays.asList(splitted));
        Map<String, Integer> mapOfStrings = new TreeMap<String, Integer>();
        for (int i = 0; i < splitted.length; i++) {
            mapOfStrings.put(splitted[i].substring(splitted[i].indexOf(" "), splitted[i].length()),Integer.valueOf(splitted[i].substring(0, splitted[i].indexOf(" "))));

        }

        for (Map.Entry<String, Integer> entry : mapOfStrings.entrySet()) {
            System.out.println(entry.getValue()+ " " + entry.getKey());
        }
    }

如何跳过和逐行读取的字母字符串数组排序

1 个答案: