Question

我有一个文本文件（statecapitals.txt），其中包含“State - Capital”：

Alaska - Juneau
Arizona - Phoenix
Arkansas - Little Rock
California - Sacramento
Colorado - Denver
Connecticut - Hartford
Delaware - Dover
Florida - Tallahassee

如何将第一个字段放入arraylist中，将第二个字段放入另一个arraylist中（我无法修改文本文件）？

Answer 1

您可以使用.split(" - ")拆分行。请参阅JavaDoc。

例如：

    String content = "Alaska - Juneau\n" +
            "Arizona - Phoenix\n" +
            "Arkansas - Little Rock\n" +
            "California - Sacramento\n" +
            "Colorado - Denver\n" +
            "Connecticut - Hartford\n" +
            "Delaware - Dover\n" +
            "Florida - Tallahassee\n";

    Scanner scanner = new Scanner(content);

    List<String> states = new ArrayList<>();
    List<String> capitals = new ArrayList<>();

    while (scanner.hasNextLine()) {
        String[] parts = scanner.nextLine().split(" - ");
        states.add(parts[0]);
        capitals.add(parts[1]);
    }

    System.out.println(states);
    System.out.println(capitals);

Answer 2

假设您已设法迭代文件的每一行，并在String中将每一行添加为List<String> lines;

您现在可以为每个字符串创建2个新List，如下所示：

List<String> states = new ArrayList<>();
List<String> capitals = new ArrayList<>();

for (String line : lines) {
    String[] words = line.split(" - ");
    if (words.length == 2) {
        states.add(words[0]);
        capitals.add(words[1]);
    }
}

文本文件为2个不同的arraylist

2 个答案: