Split string by "],[" - regex

Question

I know one back slash / can be used to escape some special characters like (, . and double back slash // can be used to escape special characters in a string directly.
I want to split:
"[[0,0,1,0,0],[0,0,0,0,0],[0,0,0,1,0],[1,1,0,1,1],[0,0,0,0,0]]"
by ],[ between each sub array.
What should I do if I want to get all the sub arrays by splitting them to be "[[0,0,1,0,0", "0,0,0,0,0","0,0,0,1,0","1,1,0,1,1", "0,0,0,0,0]]" first.
If you have better idea on how to convert them directly into sub arrays including numbers only like "0,0,1,0,0", "0,0,0,0,0","0,0,0,1,0","1,1,0,1,1", "0,0,0,0,0" that will be even better.

Answer 1

Since both [ and ] at special characters in regex you need to escape them.
you can try with below:
str.split("\\],\\[");
Test code:
String str="[[0,0,1,0,0],[0,0,0,0,0],[0,0,0,1,0],[1,1,0,1,1],[0,0,0,0,0]]";
String[] strs = str.split("\\],\\[");
for(String s:strs){
System.out.println(s);
}
Output result:
[[0,0,1,0,0
0,0,0,0,0
0,0,0,1,0
1,1,0,1,1
0,0,0,0,0]]
If you want to remove the duplicate [[ and ]],just add below codes before split:
str = str.substring(2);
str = str.substring(0, str.length()-2);
Updated answer,if you want to eliminate all the brackets in between and at both ends by regex,you write regex like \[?\[((\d,)+\d) then fetch the first group of each match record data, below is the code:
String str = "[[0,0,1,0,0],[0,0,0,0,0],[0,0,0,1,0],[1,1,0,1,1],[0,0,0,0,0]]";
String regex = "\\[?\\[((\\d,)+\\d)";
Pattern r = Pattern.compile(regex);
Matcher m = r.matcher(str);
while (m.find()) {
System.out.println(m.group(1));
}
The output is
0,0,1,0,0
0,0,0,0,0
0,0,0,1,0
1,1,0,1,1
0,0,0,0,0

Answer 2

Your input is valid JSON, so I suggest using a JSON parser.
The code would look like this:
import javax.json.*;
JsonReader jsonReader = Json.createReader(new StringReader("[[0,0,1,0,0],[0,0,0,0,0],[0,0,0,1,0],[1,1,0,1,1],[0,0,0,0,0]]"));
JsonArray array = jsonReader.readArray();
jsonReader.close();
System.out.println("Array #2: " + array.getJsonArray(1)); // should give [0,0,0,0,0]
System.out.println("Array #3, 4th value: " + array.getJsonArray(2).getInt(3)); // should give 1

Answer 3

If you want the String to convert into a 2d-Array, you can use below functions that takes the String and returns the 2d-Array of ints:
private static int[][] getMatrixFromString(String arrayStrinng) {
String arrayString = arrayStrinng.substring(1, arrayStrinng.length() - 1);
String[] splitMajor = arrayString.split("],");
int rowCount = splitMajor.length, colCount = 0;
int[][] matrix = new int[rowCount][];
for (int row = 0; row < splitMajor.length; row++) {
String[] splitMinor = splitMajor[row].split(",");
if (colCount == 0) {
colCount = splitMinor.length;
matrix = new int[rowCount][colCount];
}
for (int i = 0; i < colCount; i++) {
if (splitMinor[i].startsWith("["))
splitMinor[i] = splitMinor[i].substring(1);
if (splitMinor[i].endsWith("]"))
splitMinor[i] = splitMinor[i].substring(0, splitMinor[i].length() - 1);
matrix[row][i] = Integer.parseInt(splitMinor[i]);
}
}
return matrix;
}