java - Java中的正则表达式用于查找重复的连续单词

Question

我将此视为在字符串中查找重复单词的答案。但是当我使用它时，它认为 This 和 is 是相同的并删除了 is。

正则表达式

"\\b(\\w+)\\b\\s+\\1"

知道为什么会这样吗？

这是我用来删除重复项的代码

public static String RemoveDuplicateWords(String input)
{
    String originalText = input;
    String output = "";
    Pattern p = Pattern.compile("\b(\w+)\b\s+\b\1\b", Pattern.MULTILINE+Pattern.CASE_INSENSITIVE); 
    //Pattern p = Pattern.compile("\\b(\\w+)\\b\\s+\\1", Pattern.MULTILINE+Pattern.CASE_INSENSITIVE);
    Matcher m = p.matcher(input);
    if (!m.find())
        output = "No duplicates found, no changes made to data";
    else
    {
        while (m.find())
        {
            if (output == "")
                output = input.replaceFirst(m.group(), m.group(1));
            else
                output = output.replaceAll(m.group(), m.group(1));
        }
        input = output;
        m = p.matcher(input);
        while (m.find())
        {
            output = "";
            if (output == "")
                output = input.replaceAll(m.group(), m.group(1));
            else
                output = output.replaceAll(m.group(), m.group(1));
        }
    }
    return output;
}

Answer 1

试试这个:

String pattern = "(?i)\\b([a-z]+)\\b(?:\\s+\\1\\b)+";
Pattern r = Pattern.compile(pattern, Pattern.CASE_INSENSITIVE);

String input = "your string";
Matcher m = r.matcher(input);
while (m.find()) {
    input = input.replaceAll(m.group(), m.group(1));
}
System.out.println(input);

Java 正则表达式在 API documentation of the Pattern class 中有很好的解释。 .添加一些空格以指示正则表达式的不同部分后:

"(?i) \\b ([a-z]+) \\b (?: \\s+ \\1 \\b )+"

\b       match a word boundary
[a-z]+   match a word with one or more characters;
         the parentheses capture the word as a group    
\b       match a word boundary
(?:      indicates a non-capturing group (which starts here)
\s+      match one or more white space characters
\1       is a back reference to the first (captured) group;
         so the word is repeated here
\b       match a word boundary
)+       indicates the end of the non-capturing group and
         allows it to occur one or more times