如何在没有分隔符的情况下拆分单词并对 Java 8 中的拆分字符串执行操作？

Question

This is the code that I have created. I want to Split a word - "UUDDUUDD". I want to perform an operation on every character that I receive from this word. So, I tried using the below code.I'm getting the error as

error: incompatible types: String cannot be converted to String[]

If I'm not using an array ie String[] newPath and just write as String newPath , I would not be able to perform iteration operation over the string. Can you help me to know how can I iterate over the new array?

for (String[] newPath: path.split(""))

for (char[] newPath: path.split("")
           {
               if (newPath[i]=="U")
               {
                  count++; 
               }
               else
               {
                  count= count-1; 
               }                
           }

Answer 1

You have to use toCharArray() that's convert String into char[] . Remeber for char use 'U' not "U" . Here is a correct code:

public static void main(String[] args) {
    String path = "UUDDUUDD";
    int count = 0;
    
    for (char newPath: path.toCharArray()) {
        if (newPath == 'U') {
            count++;
        } else {
            count--;
        }
    }
}

Answer 2

Split function returns a String array. In your for loop you should iterate over these values by using a simple String, so newPath is a String, not a String array. If you want just count 'U' chars in String:

   public static void main(String[] args) {
        String path = "UUDDUUDD";
        long count = path.chars()
            .filter(ch -> ch == 'U')
            .count();

        System.out.println("number of Us: " + count);
    }

Increment count if char is 'U' and decrement otherwise:

public static void main(String[] args) {
    String path = "UUDDUUDD";

    long countResult = path.chars()
        .reduce(0, (i, j) -> j == 'U' ? i + 1 : i - 1);

    System.out.println(countResult);
}

Answer 3

The return type of String.split() is String[].

So if we are iterating over the result of String.split() we use a String:

class Test {
    public static void main(String[] args) {
        for (String c : "ABCD".split("")) {
            System.out.println(c);
        }
    }
}