Convert String into a two dimensional array

Question

I try to convert this string

s=[[4, 2, 2, 4], [3, 4, 5, 6], [6, 7, 8, 9], [3, 2, 1, 4]]
into a two dimensional array like this
{4, 2, 2, 4},
{3, 4, 5, 6},
{6, 7, 8,9},
{3, 2, 1, 4}

by use this code

 int e=s.replaceAll("\\[", "").replaceAll(" ","").replaceAll("],","]").length();
        String[] rows1 = s.replaceAll("\\[", "").replaceAll(" ","").replaceAll("],","]").substring(0, e-2).split("]");

        String[][] matrix1 = new String[4][4]; 
        int r1 = 0;
        for (String row1 : rows1) {
            matrix[r1++] = row1.split(",");
        }

        System.out.println(Arrays.deepToString(matrix1));

But is have problem like this

Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 3 at test.main(test.java:94)

Can you help me find a solution?

Did you look up an ArrayIndexOutOfBoundsException to make an effort to understand what it is and why it happens? Did you use your debugger to step through the code? — tnw
– tnw, Commented Apr 9, 2015 at 18:54
I think your trying to alter the wrong variable here matrix[r1++] = row1.split(",");. Shouldn't it be matrix1? Try using variable names which do a little bit in explaining what the variables role is. — ug_
– ug_, Commented Apr 9, 2015 at 18:59

Md. Nasir Uddin Bhuiyan · Accepted Answer · 2017-08-04 03:09:42Z

9

I think this code will help you. Read the all comments carefully.

     String s="[[4, 2, 2, 4], [3, 4, 5, 6], [6, 7, 8, 9], [3, 2, 1, 4]]";
     s=s.replace("[","");//replacing all [ to ""
     s=s.substring(0,s.length()-2);//ignoring last two ]]
     String s1[]=s.split("],");//separating all by "],"

     String my_matrics[][] = new String[s1.length][s1.length];//declaring two dimensional matrix for input

     for(int i=0;i<s1.length;i++){
         s1[i]=s1[i].trim();//ignoring all extra space if the string s1[i] has
         String single_int[]=s1[i].split(", ");//separating integers by ", "

         for(int j=0;j<single_int.length;j++){
             my_matrics[i][j]=single_int[j];//adding single values
         }
     }

     //printing result
     for(int i=0;i<4;i++){
         for(int j=0;j<4;j++){
             System.out.print(my_matrics[i][j]+" ");
         }
         System.out.println("");
     }

[[4, 2, 2, 4], [3, 4, 5, 6], [6, 7, 8, 9], [3, 2, 1, 4]]

Logic: 1) replacing all [ to "" now I have-> 4, 2, 2, 4], 3, 4, 5, 6], 6, 7, 8, 9], 3, 2, 1, 4]]

2) Separating all by "]," now I have->

A) 4, 2, 2, 4

B) 3, 4, 5, 6

c) 6, 7, 8, 9

d) 3, 2, 1, 4

3) Separating A B C D by ", " now I have->

A) a) 4 b) 2 c) 2 d) 4

B) a) 3 b) 4 c) 5 d) 6

c) a) 6 b) 7 c) 8 d) 9

d) a) 3 b) 2 c) 1 d) 4

edited Aug 4, 2017 at 3:09

answered Apr 9, 2015 at 19:19

Md. Nasir Uddin Bhuiyan

1,5961 gold badge14 silver badges24 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

Phoenix Over a year ago

ok. But this line : s1[i]=s1[i].trim(); just make result more beautifull, right?

Michael Dz · Accepted Answer · 2018-01-07 12:51:49Z

4

Solution using Java streams:

String[][] arr = Arrays.stream(str.substring(2, str.length() - 2).split("\\],\\["))
.map(e -> Arrays.stream(e.split("\\s*,\\s*"))
.toArray(String[]::new)).toArray(String[][]::new);

answered Jan 7, 2018 at 12:51

Michael Dz

3,87410 gold badges51 silver badges79 bronze badges

Comments

Shar1er80 · Accepted Answer · 2015-04-09 19:43:28Z

1

Try this...

String s="[[4, 2, 2, 4], [3, 4, 5, 6], [6, 7, 8, 9], [3, 2, 1, 4]]";

// Split on this delimiter
String[] rows = s.split("], \\[");
for (int i = 0; i < rows.length; i++) {
    // Remove any beginning and ending braces and any white spaces
    rows[i] = rows[i].replace("[[", "").replace("]]", "").replaceAll(" ", "");
}

// Get the number of columns in a row
int numberOfColumns = rows[0].split(",").length;

// Setup your matrix
String[][] matrix = new String[rows.length][numberOfColumns];

// Populate your matrix
for (int i = 0; i < rows.length; i++) {
    matrix[i] = rows[i].split(",");
}
// Display your matrix
System.out.println(Arrays.deepToString(matrix));

Results:

enter image description here

answered Apr 9, 2015 at 19:43

Shar1er80

9,0512 gold badges24 silver badges31 bronze badges

Comments

Bram · Accepted Answer · 2015-04-09 19:09:53Z

0

This just doesn't add the comma's at the end of the line:

    String s = "[[4, 2, 2, 4], [3, 4, 5, 6], [6, 7, 8, 9], [3, 2, 1, 4]]";
    for (String l: s.split("\\]\\s*,\\s*\\[")) {
        l = l.replaceAll("\\[", "").replaceAll("\\]", "");
        System.out.println("{" + l + "}");
    }

answered Apr 9, 2015 at 19:09

Bram

4792 silver badges10 bronze badges

Comments

kyle · Accepted Answer · 2015-04-09 19:11:47Z

0

Assuming that the input string will always be in that format, with 4 integers between each bracket, I think the best way to do it would simply be to use a Scanner object and it's nextInt() method which will ignore the brackets and comma's and just find the numbers. Then put them into a 2d array like how you would with a loop.

It kinda gets rid of all the fun you were having with removing the brackets though, so it's not really better in terms of making an exercise out of this.

answered Apr 9, 2015 at 19:11

kyle

711 gold badge1 silver badge4 bronze badges

Collectives™ on Stack Overflow

Convert String into a two dimensional array

5 Answers 5

1 Comment

Comments

Comments

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

5 Answers 5

1 Comment

Comments

Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related