不将单词保存在数组中 [英] Doesn't save the words in array

问题描述

我有一个可能很简单的问题。我尝试读取文件，并且想将每个单词添加到数组短语中。问题发生在for循环中。我得到了异常索引0超出长度0的界限。
您能帮我吗？

i've got a propably simple question. I try to read the file and i want to add each single word to my array "phrase". The problem occures in for loop. I got the exception "index 0 out of bounds for length 0". Can you please help me with that?

    String [] tokens;
    String line;
    String hash = " ";
    int n = 0;
    String [] phrase = new String [n];

    public void loadFile()
    {
        try
        {
            @SuppressWarnings("resource")
            BufferedReader br = new BufferedReader(new FileReader("z3data1.txt"));

            while((line = br.readLine()) != null)
            {
                tokens = line.split("[ ]");
                n += tokens.length;
            }
            for(int j = 0; j<tokens.length; j++)
            {
                phrase[j] = tokens[j];
            }
        }
        catch(IOException ex)
        {
            ex.printStackTrace();
        }
   }

推荐答案

A

• 由于数组不够大且索引 j而出现错误超出了大小。


• 您一直在 while循环中覆盖令牌。 while循环需要包含将令牌复制到短语数组。

• you are getting the error because your array is not large
  enough and the index j is exceeding its size.
• you keep overwriting tokens in the while loop. The while loop needs to encompass the copying of the tokens to the phrase array.

因此，请尝试以下操作：

So try the following:

      while((line = br.readLine()) != null) {
              tokens = line.split("[ ]");
              n += tokens.length; // don't really need this.
          //starting offset to write into phrase
          int len = phrase.length;
          phrase = Arrays.copyOf(phrase,phrase.length + tokens.length);

          for(int j = 0; j<tokens.length; j++) {
              phrase[j + len] = tokens[j];
          }
       }

此语句

phrase = Arrays.copyOf(phrase,phrase.length + tokens.length)

复制短语的内容并增加数组大小以处理令牌的编写。

Copies the contents of phrase and increases the array size to handle the writing of tokens.

另一种（可能是首选的）替代方法是使用 List< String> 随需要而增长。

Another (and probably preferred) alternative is to use a List<String> which grows as you need it.

List<String> phrase = new ArrayList<>();

for(int j = 0; j<tokens.length; j++) {
       phrase.add(tokens[j]);
}
// or skip the loop and just do
Collections.addAll(phrase,tokens);

一个观察。我不知道您要拆分的内容，但您的拆分语句看起来可疑。

One observation. I don't know what you are splitting on but your split statement looks suspicious.

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