Using String.split() to access numeric values

Question

i tried myself lot but can't get a solution so i'm asking help.

i have an string String input="---4--5-67--8-9---";

now i need to convert in into an string array which will look like:

String [][]output={{4},{5},{67},{8},{9}};

i tried with split() and

java.util.Arrays.toString("---4--5-67--8-9---".split("-+")

but can't find the desired answer. so what to do?

actually i need the value 4,5,67,8,9.but i'm not sure how to find them. i will treat the values as integer for further processing

Answer 1

String[] numbers = "---4--5-67--8-9---".split("-+");
String[][] result = new String[numbers.length][1];
for (int i = 0; i < numbers.length; i++) {
    result[i][0] = numbers[i];
}

Update: to get rid of the initial empty value, you can get a substring of the input, like:

int startIdx = 0;
char[] chars = input.toCharArray();
for (int i = 0; i < chars.length; i ++) {
    if (Character.isDigit(chars[i])) {
        startIdx = i;
        break;
    }
}
input = input.substring(startIdx);

(or you can check them for not being empty (String.isEmpty()) when processing them later.)

Answer 2

First, here is the answer to your question. This code will generate a two-dimensional array where each element is an array consisting of a single numeric string.

final String input = "---4--5-67--8-9---";
// desired output: {{4},{5},{67},{8},{9}}

// First step: convert all non-digits to whitespace
// so we can cut it off using trim()
// then split based on white space
final String[] arrayOfStrings =
    input.replaceAll("\\D+", " ").trim().split(" ");

// Now create the two-dimensional array with the correct size
final String[][] arrayOfArrays = new String[arrayOfStrings.length][];

// Loop over single-dimension array to initialize the two-dimensional one
for(int i = 0; i < arrayOfStrings.length; i++){
    final String item = arrayOfStrings[i];
    arrayOfArrays[i] = new String[] { item };
}
System.out.println(Arrays.deepToString(arrayOfArrays));
// Output: [[4], [5], [67], [8], [9]]

However, I think what you really need is an array of Integers or ints, so here is a revised solution:

final String input = "---4--5-67--8-9---";

// Convert all non-digits to whitespace
// so we can cut it off using trim()
// then split based on white space
final String[] arrayOfStrings =
    input.replaceAll("\\D+", " ").trim().split(" ");

// Now create an array of Integers and assign the values from the string
final Integer[] arrayOfIntegers = new Integer[arrayOfStrings.length];
for(int i = 0; i < arrayOfStrings.length; i++){
    arrayOfIntegers[i] = Integer.valueOf(arrayOfStrings[i]);
}
System.out.println(Arrays.toString(arrayOfIntegers));
// Output: [4, 5, 67, 8, 9]

// Or alternatively an array of ints
final int[] arrayOfInts = new int[arrayOfStrings.length];
for(int i = 0; i < arrayOfStrings.length; i++){
    arrayOfInts[i] = Integer.parseInt(arrayOfStrings[i]);
}
System.out.println(Arrays.toString(arrayOfInts));
// Output: [4, 5, 67, 8, 9]

Whether you use the Integer or the int version really depends on whether you want to just do some math (int) or need an object reference (Integer).

Answer 3

public class split{
public static void main(String[] argv){
    String str="---4--5-67--8-9---";
    String[] str_a=str.split("-+");
}

}

This seems to working for me.

Answer 4

String[] result = "---4--5-67--8-9---".split("-+");
int i;
for (i = 0; i < result.length; i++) {
    if (result[i].length() > 0) {
        System.out.println(result[i]);
    }
}

gives me output:

4
5
67
8
9

Answer 5

Using a regex pattern seems more natural in this case:

public class split {
     public static int[] main(String input) {

         ArrayList<String> list = new ArrayList() ;

         Pattern pattern = Pattern.compile("[0-9]") ;
         Matcher matcher = pattern.matcher(input) ;

         String match = null ;

             while(  ( match = matcher.find() )  ===  true  ) {
                 list.add(match) ;
             }

         String[] array = list.toArray(   new String[  ( list.size() )  ]()   ) ;

         return array ;

     }
}

Answer 6

    String input="---4--5-67--8-9---";
    Scanner scanner = new Scanner(input).useDelimiter("-+");
    List<Integer> numbers = new ArrayList<Integer>();
    while(scanner.hasNextInt()) {
        numbers.add(scanner.nextInt());
    }
    Integer[] arrayOfNums = numbers.toArray(new Integer[]{});
    System.out.println(Arrays.toString(arrayOfNums));

Answer 7

I thought the following is quite simple, although it uses List and Integer arrays, Its not that an overhead for small strings:

For simplicity, I am returning a single dimension array, but can be easily modified to return an array you want. But from your question, it seems that you just want a list of integers.

import java.util.*;

public class Test {

    public static void main(String[] args) throws Throwable {
         String input = "---4--5-67--8-9---";
         System.out.println(split(input).length); // 5
    }

    public static Integer[] split(String input) {
         String[] output = input.split("\\-+");
         List<Integer> intList = new ArrayList<Integer>(output.length);

         // iterate to remove empty elements
         for(String o : output)  {
            if(o.length() > 0)   {
               intList.add(Integer.valueOf(o));
            }
         }
         // convert to array (or could return the list itself
         Integer[] ret = new Integer[intList.size()];
         return intList.toArray(ret);
    }
}

Answer 8

I might be late to the party but I figured I'd give the guava take on this.

    String in = "---4--5-67--8-9---";

    List<String> list = Lists.newArrayList(Splitter.on("-").omitEmptyStrings().trimResults().split(in));
    System.out.println(list);
    // prints [4, 5, 67, 8, 9]