如何排序包含数字的字符串集合？ [英] How to sort a String collection that contains numbers?

问题描述

我有一个包含如下数据的字符串向量：

I have a String Vector that contains data like this :

5:34，5:38，17:21，22： 11，...

5:34, 5:38, 17:21, 22:11, ...

如果我尝试使用 Collections.sort（...）; 它将显示如下：

If i try to merge this using Collections.sort( ... ); it will appear like this :

17:21，22:11，5:34，5:38

17:21, 22:11, 5:34, 5:38

其实我希望它像这样出现：

Actually i want it to appear like this :

34，5:38，17:21，22:11

5:34, 5:38, 17:21, 22:11

所以我想根据冒号前的数字排序元素：，那么如果一些元素在：之前有相同的数字，则根据：后的数字对它们进行排序。

So i want to sort the elements according to the number before the colon ":" then if some elements have the same number before ":" then sort them according to the number after the ":".

推荐答案

您可以创建一个自定义 Comparator 拆分 String 并将其解析为两个int 或创建一个定制类来表示每个 String ，并将其存储在 Collection 中。我赞成后一种方法，因为你只产生分割/解析字符串一次的开销;例如

You could either create a custom Comparator to split the String and parse it into two ints, or create a bespoke class to represent each String and store that in the Collection instead. I favour the latter approach as you only incur the overhead of splitting / parsing the String once; e.g.

public class Data implements Comparable<Data> {
  private final int prefix;
  private final int suffix;

  public Data(String str) {
    String[] arr = str.split(":");

    if (arr.length != 2) {
      throw new IllegalArgumentException();
    }

    this.prefix = Integer.parseInt(arr[0]);
    this.suffix = Integer.parseInt(arr[1]);
  }

  public int compareTo(Data data) {
    // Should really avoid subtraction in case of overflow but done to keep code brief.
    int ret = this.prefix - data.prefix;

    if (ret == 0) {
      ret = this.suffix - data.suffix;
    }

    return ret;
  }

  // TODO: Implement equals and hashCode (equals to be consistent with compareTo).

  public String toString() { return String.format("%d:%d", prefix, suffix); }
}

然后它只是一个存储一些数据集合中的对象;例如

Then it's simply a case of storing some Data objects in your Collection; e.g.

List<Data> l = new ArrayList<Data>();
l.add(new Data("13:56"));
l.add(new Data("100:16"));
l.add(new Data("9:1"));
Collections.sort(l);

还有一件事 - 你提到你使用 Vector 。您应该尽量避免使用向量 / Hashtable ，因为这些已被 code> / Map ，作为JDK 1.2中的集合框架的一部分。

One more thing - You mention you're using a Vector. You should try to avoid using Vector / Hashtable as these have been superseded by List / Map, which were introduced as part of the Collections Framework in JDK 1.2.

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