分割字符串

Question

I have a String line which can be

AND A B C -> D
OR A B -> D
NAND A B C D E -> F
............

How can I split the String line into just ABCD without the first String token (AND, OR, NAND) and without -> and should trim the whitespaces? I have done here but it gives me an output

or A B C
D

public static void main(String [] args)throws IOException
    {
        String str = "or A B C -> D";
        String[] array = str.split("->");
        String[] leftSide = array[0].trim().split(array[0]);
        String[] rightSide = array[1].trim().split(" ");

        for(int i = 0; i < leftSide.length; i++)
        {
            System.out.println(leftSide[i]);
        }

        for(int i = 0; i < rightSide.length; i++)
        {
            System.out.println(rightSide[i]);
        }
    }

Answer 1

        String str = "AND A B C -> D";
        // \\s+ for multiple white spaces  -> is for your request
        StringTokenizer st = new StringTokenizer(str, "\\s+ ->");

        boolean isFirstToken = true;
        while (st.hasMoreTokens()) {
            if (isFirstToken) {
                isFirstToken = false;
                st.nextToken();//For first iteration
                continue;
            }
            System.out.print(st.nextToken() + " ");
        }

Answer 2

Split the string by a space " " and then iterate through the resulting array, removing any sequence that is more than 1 symbol.

    String str = "or A B C -> D";
    String[] array = str.split(" ");
    List<String> list = Arrays.asList(array);
    String currentString;

    for(int i = 0; i < list.size(); i++)
    {
        currentString = list.get(i);

        if(currentString.length() >1) {
             list.remove(currentString);
        }
    }

     System.out.println(list);

Answer 3

What's happening is you're splitting on "->", giving "or ABC " and " D". Then you're trimming them, then splitting them on nothing in particular (you split the left side by itself, and the right side by " " but "D" has no spaces to split on. That's giving you the results you see.

You can just define all the stuff that's valid in some array and then split everything, then only keep the stuff that's valid.

public static final String[] VALUES = new String[] {"A","B","C","D"};
public static void main(String [] args)
{
    String str = "or A B C -> D";
    String[] array = str.split(" ");
    for (int i = 0; i < array.length; i++) {
        if (Arrays.asList(VALUES).contains(array[i])) {
            System.out.print(array[i] + " ");
        }
    }
}

Alternatively, you can do this the other way around if that makes more sense for your application - define a list of terms that should NOT be included instead.

public static final String[] EXCLUDE = new String[] {"AND", "OR", "->"};
public static void main(String [] args)
{
    String str = "or A B C -> D";
    String[] array = str.split(" ");
    for (int i = 0; i < array.length; i++) {
        if (!(Arrays.asList(EXCLUDE).contains(array[i]))) {
            System.out.print(array[i] + " ");
        }
    }
}