java - 删除多次出现的单词

Question

如何删除 String 中多次出现的单词？这里最难的是，我不知道它是哪个词。请参阅以下示例。

This is how how I tried to split a paragraph into a sentence sentence But, there is a problem My paragraph includes dates dates dates dates like Jan 13, 2014 , words includes like U S and numbers

这里，一些词有多次出现。 sentence、dates、includes 和how 等词不止一次出现。请注意，这种重复可能不会彼此靠近，例如 includes。我想删除这些，所以它会像下面这样。

This is how I tried to split a paragraph into a sentence But, there is a problem My paragraph includes dates like Jan 13, 2014 , words like U S and numbers

请注意，删除多次出现并不意味着删除多次出现的单词的所有出现。它只会保留一个副本并删除其余副本。

就像上面一样，会有非常大的String，我不知道哪个单词出现了不止一次。我怎样才能做到这一点？

Answer 1

一次一个单词地复制文本，并在整个过程中忽略重复项。使用哈希集来跟踪重复项。

像这样的……

String text = "This is how how I tried to split a paragraph into a sentence sentence But, there is a problem My paragraph includes dates dates dates dates like Jan 13, 2014 , words includes like U S and numbers"; 
StringBuilder result = new StringBuilder();
HashSet<String> set = new HashSet<String>();
for(String s : text.split(" ")) {
    if (!set.contains(s)) {
        result.append(s);
        result.append(" ");
        set.add(s);
    }
}
System.out.println(result);

您必须稍微修改一下才能正确处理标点符号，但这应该让您入门。