如何在Java中使用split（）字符串方法分隔单词

Question

I want to separate words and print them in a single line with a hyphen(-) in between. I have written the following code but it only prints the last word followed by a hyphen ie the output is carrot-. I don't understand why and what changes do I make to get the desired output?

public class SeparatingWords {

    public static void main(String[] args) {
        String str = "apple banana carrot";
        System.out.println(separatingWords(str));
    }

    public static String separatingWords(String str) {
        String[] words = str.split(" ");
        String result = null;

        for (int i = 0; i < words.length; i++) {
            result=words[i]+"-";
        }

        return result;
    }
}

Answer 1

Instead of calling a split and concatenating the string, why can't you directly call replaceAll directly to achieve your goal. This will make your code simple.

String result = str.replaceAll(" ", "-");

Below is sample modified code of yours. Hope this helps

public class Sample {

public static void main(String[] args) {
    String str = "apple banana carrot";
    System.out.println(separatingWords(str));
 }

public static String separatingWords(String str) {
    String result = str.replaceAll(" ", "-");
    return result;
 }
}

If you want to perform any other operation based on your requirement inside the method, then below should work for you. As suggested by @Moler added += and initialized the result object

public static String separatingWords(String str) {
    String[] words = str.split(" ");
    String result = "";  // Defaulted the result

    for (int i = 0; i < words.length-1; i++) {
        result += words[i] + "-";  // Added a +=
    }
    result += words[words.length - 1];
    return result;
}

Answer 2

   public class SeparatingWords
    {
        public static void main(String[] args)
        {
            String str="apple banana carrot";
            System.out.println(separatingWords(str));
        }
        public static String separatingWords(String str)
        {
            String[] words=str.split(" ");
            String result="";

            for(int i=0;i<words.length;i++)
            {
                result += words[i]+"-";
            }
            return result;
        }
    }

Answer 3

Try this code:

public class SeparatingWords
{
public static void main(String[] args)
{
    String str="apple banana carrot";
    System.out.println(separatingWords(str));
}
public static String separatingWords(String str)
{
    String[] words=str.split(" ");

    String result=words[0];

    for(int i=1;i<words.length;i++)
    {
        result=result+"-"+words[i];
    }
    return result;
}
}

Answer 4

You could use s StringBuilder , append the single word and a hyphon and at the last word, you just append the word:

public class SeparatingWords {

    public static void main(String[] args) {
        String str = "apple banana carrot";
        System.out.println(separatingWords(str));
    }

    public static String separatingWords(String str) {
        String[] words = str.split(" ");
        StringBuilder resultBuilder = new StringBuilder();

        for (int i = 0; i < words.length; i++) {
            resultBuilder.append(words[i]);
            if (i != words.length - 1) {
                resultBuilder.append("-");
            }
        }

        return resultBuilder.toString();
    }
}

Answer 5

String[] words = str.split(" ");
// perform operations on individual words
return String.join("-", words);