Convert ArrayList into 2D array containing varying lengths of arrays
arraylist, indexing, java, multidimensional-array, varying
Solution
String[][] array = new String[arrayList.size()][];
for (int i = 0; i < arrayList.size(); i++) {
ArrayList<String> row = arrayList.get(i);
array[i] = row.toArray(new String[row.size()]);
}
where `arrayList` is your `ArrayList<ArrayList<String>>` (or any `List<List<String>>`, change the first line inside the `for` loop accordingly)
Problem
So I have: ``` ArrayList<ArrayList<String>> ``` Which contains an x number of ArrayLists which contain another y number of Strings.. To demonstrate: ``` Index 0: String 1 String 2 String 3 Index 1: String 4 Index 2: Index 3: String 5 String 6 ``` Where index refers to the array index containing a string. How can I transform this into a 2D array which looks like: ``` {{String1, String2, String3},{String4}, {}, {String5, String6}} ``` Thank you so much.