需要帮助按字母顺序排序文本文件

时间:2015-04-08 20:44:07

标签: java arrays sorting arraylist

好的所以我需要列出未分类的单词:

freddy
at
elephant
whoooooodat
alice
tommy
bobby
it
at
about

按长度和字母顺序排序:

at
at
it
about
alice
bobby
tommy
freddy
elephant
whoooooodat

我可以使用Collections.sort(单词)对其进行排序并获取:

at
it
at
alice
tommy
bobby
about
freddy
elephant
whoooooodat

我只需要帮助按字母顺序排列。

继承我目前的代码:

public class Lab1
{
    public static void main( String args[] ) throws IOException
    {
        Scanner file = new Scanner(new File("lab1.dat"));

        ArrayList<Word> words = new ArrayList<Word>();
        while(file.hasNext())
        {
            //add in a new Word to words
            words.add(new Word(file.next()));
        }

        //can sort the words with this 
        Collections.sort(words);


        //make letter lower case and compare asii values
        // need to sort the words by alphabetically 
        /*
        for (int i = 0; i < words.size()-1 ; i++)
        {
            int min = i; 
            for(int j= i+1; j < words.size(); j++){
                String minstring = (String)words.get(min);
            if((((String)words.get(min)).toLowerCase()).compareTo(words.get(j)) > 0)
                min =j;



            }// end of inner loop

            if (min!= i){
            Word temp = words.get(min); 
            words.set(min,words.get(i));
            words.set(i,temp);
            }// end of sort if

        }   //end of outer loop
*/
        //print out words
        for (int j =0; j < words.size(); j++)
        System.out.println(words.get(j));
    }
}

 //Second Part
public class Word implements Comparable<Word>
{
    private String word;

    //constructors

    public Word()
    {
        word = "";
    }
    public Word(String a)
    {
        word =a;
    }



    //compareTo

    public int compareTo(Word other)
    {
        /*if (word.equals(other))
        {   
            if((word.charAt(0)).toLowerCase() )

        }*/
        return word.length() - other.word.length();
    }


    public String toString()
    {
        return word;

    }

}

如果你能帮助我那会很棒......

2 个答案:

答案 0 :(得分:2)

public class MyComparator implements Comparator<String>{
    @Override
    public int compare(String o1, String o2) {  
      if (o1.length() > o2.length()) {
         return 1;
      } else if (o1.length() < o2.length()) {
         return -1;
      }
      return o1.compareTo(o2);
    }
}

然后:

Collections.sort(yourList, new MyComparator());

答案 1 :(得分:0)

您的比较方法还应按字母顺序实现:

public int compareTo(Word other)
    {
        int difference = word.length() - other.word.length();
        if(difference == 0){
            return word.compareToIgnoreCase(other.word);
        else{
            return difference;    
        }

    }
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