I'm jsut learning java and working on a homework problem. Our assignment was two read two word lists into arrays and then combine them into one arrayList alternating the words in the list. e.g. L1[0], L2[0], L1[1], L2[1], etc.

I've got my code almost running EXCEPT if the word lists are not exactly the same length, I either leave off the last words in the longer list or I get an out of bounds index for the shorter list. I know there msut be an obvious solution I haven't thought of. Thanks for your help!

Here is the code I've written:

public class ArrayMixer {
    public static void main (String[] args){
        Scanner scnr= new Scanner(System.in); // set up scanner

        // Initialize variables to capture user inputs
        String firstLine;
        String secondLine;

        //collect user input for first list
        System.out.println("Please enter the first word list:"); // prompt user for first list
        firstLine= scnr.nextLine();
        String[] firstArray= firstLine.split(" "); // creates array to store first line split by spaces

        //System.out.println(firstLine);//FIXME COMMENT OUT AFTER TESTING
        //System.out.println(Arrays.toString(firstArray));//FIXME COMMENT OUT AFTER TESTING

        //collect user input for second list
        System.out.println("Please enter the second word list:");// prompt user for second list
        secondLine= scnr.nextLine();//
        String[] secArray= secondLine.split(" ");//create array to store second list split by spaces

        //System.out.println(secondLine);//FIXME COMMENT OUT
        //System.out.println(Arrays.toString(secArray)); //FIXME COMMENT OUT


        //Create array list called mixList to store combination of list 1 and 2
        ArrayList <String> mixList = new ArrayList<String>();

        // need to find out size of two lists put together
        int mixSize= (firstArray.length   secArray.length);
        System.out.println(mixSize);

        
//HERE IS MY PROBLEM I've replace secArray.length w/ mxSize, and firstArray.length NO DICE
for (int i=0; i< secArray.length;   i) {//FIXME NEED TO FIGURE OUT HOW TO GET THE LOOP
            // NOT GO OUT OF BOUNDS
            mixList.add(firstArray[i]);
            mixList.add(secArray[i]);
        }

        //print new list to output
        for (int i=0; i< mixList.size();   i) {
            String tempWord=mixList.get(i);
            System.out.println(tempWord);
        }

    }
}

I've tried using the length of the two lists combined and the length of the longer list-> index out of bounds, the shorter list- last words of longer list left off becuase the loop never gets to their index.

Is there some sort of special arrayList for loop I can use?

CodePudding user response：

Here is one way to combine them. You will need to adapt this to your specific requirements.

 List<Integer> evens = List.of(2, 4, 6, 8, 10, 12);
 List<Integer> odds = List.of(1, 3, 5);
 List<Integer> combined = new ArrayList<>();
 for (int i = 0, k = 0; i   k < evens.size()   odds.size(); ) {
     if (i < odds.size()) {
         combined.add(odds.get(i  ));
     }
     if (k < evens.size()) {
         combined.add(evens.get(k  ));
     }
 }
 System.out.println(combined);

And here is another.

 for (int i = 0; i < Math.max(odds.size(), evens.size()); i  ) {
    if (i < odds.size()) {
        combined.add(odds.get(i));
    }
    if (i < evens.size()) {
        combined.add(evens.get(i));
    }
 }
 System.out.println(combined);

both print

[1, 2, 3, 4, 5, 6, 8, 10, 12]

CodePudding user response：

final String[] firstArray = firstLine.split(" ");
final String[] secondArray = secondLine.split(" ");
final List<String> mixList = new ArrayList<>();

final int largerArray = Math.max(firstArray.length, secondArray.length);
for (int i = 0; i < largerArray; i  ) {
    
    if (i < firstArray.length) {
        mixList.add(firstArray[i]);
    }
    if (i < secondArray.length) {
        mixList.add(secondArray[i]);
    }
}