java 正则表达式：将具有一定字符数的单词大写

Question

我正在尝试将超过 5 个字符的字符串中的单词大写。

我能够使用 .length 检索大于 5 个字符的单词数，我可以排除大于 5 个字符的单词，但我无法将它们大写。

例如。输入："i love eating pie"

例如。输出："i love Eating pie"

这是我的代码：

 public static void main(String[] args) {
    String sentence = "";
    Scanner input = new Scanner(System.in);

    System.out.println("Enter a sentence: ");
    sentence = input.nextLine();
    String[] myString = sentence.split("\s\w{6,}".toUpperCase());
     for (String myStrings : myString) {
         System.out.println(sentence);
         System.out.println(myStrings);
         }

Answer 1

以space作为分隔符拆分输入句子，如果长度大于5则使用intiCap方法：

PS: System.out.print 将替换为 StringBuilder。

String delim = " ";
String[] myString = sentence.split(delim);

for (int i = 0; i < myString.length; i++) {
    if (i != 0) System.out.print(delim);

    if (myString[i].length() > 5)
        System.out.print(intiCap(myString[i]));
    else
        System.out.print(myString[i]);
}


private static String intiCap(String string) {
    return Character.toUpperCase(string.charAt(0)) + string.substring(1);
}

Answer 2

String sentence = "";
StringBuilder sb = new StringBuilder(sentence.length());
Scanner input = new Scanner(System.in);

System.out.println("Enter a sentence: ");
sentence = input.nextLine();
/*
 * \s (match whitespace character)
 * (<?g1> (named group with name g1)
 * \w{6,}) (match word of length 6) (end of g1)
 * | (or)
 * (?<g2> (named group with name g2)
 * \S+) (match any non-whitespace characters) (end of g2)
 */
Pattern pattern = Pattern.compile("\s(?<g1>\w{6,})|(?<g2>\S+)");
Matcher matcher = pattern.matcher(sentence);

//check if the matcher found a match
while (matcher.find())
{
    //get value from g1 group (null if not found)
    String g1 = matcher.group("g1");
    //get value from g2 group (null if not found)
    String g2 = matcher.group("g2");

    //if g1 is not null and is not an empty string
    if (g1 != null && g1.length() > 0)
    {
        //get the first character of this word and upercase it then append it to the StringBuilder
        sb.append(Character.toUpperCase(g1.charAt(0)));
        //sanity check to stop us from getting IndexOutOfBoundsException
        //check if g1 length is more than 1 and append the rest of the word to the StringBuilder
        if(g1.length() > 1) sb.append(g1.substring(1, g1.length()));
        //append a space
        sb.append(" ");
    }
    //we only need to check if g2 is not null here
    if (g2 != null)
    {
        //g2 is smaller than 5 characters so just append it to the StringBuilder
        sb.append(g2);
        //append a space
        sb.append(" ");
    }
}
System.out.println("Original Sentence: " + sentence);
System.out.println("Modified Sentence: " + sb.toString());

Answer 3

您可以使用以下内容（简短而贴心：P）：

Pattern p = Pattern.compile("(?=\b\w{6,})([a-z])\w+");
Matcher m = p.matcher(sentence);
StringBuffer s = new StringBuffer();
while (m.find()){
    m.appendReplacement(s, m.group(1).toUpperCase() + m.group(0).substring(1));
}
System.out.println(s.toString());

见Ideone Demo

java 正则表达式：将具有一定字符数的单词大写

java regex: capitalize words with certain number of characters

java

regex

string

character