打印时将每行中相同值的数组元素分组 - Java

Question

there is a way to print elements of a String array sorted for word length at every line? So, considering the code below,

String[] arr = {"a", "b", "cc", "dd", "ee", "fff", "hhh"};
            
    for (int i = 0; i < 5; i++) {
        System.out.println(arr[i]);
    }

there is a way to change the output from:

"ab cc dd ee fff hhh"

to

"ab

cc dd ee

fff hhh"

Thanks for any help.

Answer 1

I would use stream for that job:

Arrays.stream(arr).collect(
            Collectors.groupingBy(String::length, 
                    Collectors.joining(" ")))
      .values().forEach(System.out::println);
    

Output:

a b
cc dd ee
fff hhh

Answer 2

Before spoilering the answer, I will give you some hints:

1. Create a variable that stores the length of the previous string. (Set to Integer.MAX_Value for beginning)
2. Iterate through the array. If the previousLength is smaller than the length of the currentString, insert a newline.
3. Print the current string with a whitespace at the end.
4. Set the variable in 1 to the length of the current string
5. End of the loop

Please try to code this yourself, as this helps you to better understand Java.

Answer 3

So here is my take on this problem. It doesn't involve using indices and avoids streams as this is not something a beginner should start with.

   public static void main(String[] args) {
        String[] arr = {"a", "b", "cc", "dd", "ee", "fff", "hhh"};
        int previousLength = Integer.MAX_VALUE;
    
        for (String currentString: arr){
            if(previousLength < currentString.length()){
                System.out.println("");
            }
            System.out.print(currentString+" ");
            previousLength = currentString.length();
        }
    }