How can I parse a string representing an array of arrays?

Question

I get from an url a result as:

[[1509321600000,35166.44],[1509408000000,35224.31],[1509580800000,35234.60]]

it is a String, and I want to transform to an array of arrays.

Does a function exist for that? Or do I have to use explode function and create the array manually?

It is valid json. Try this tool to get this verified:http://json-validator.com/ — MEE, Nov 03 '17 at 11:42
no, why would you want to replace anything? Check e.g. jsonlint, it is perfectly fine. — luk2302, Nov 03 '17 at 11:43
@user1450740 if u see json that doesn't meant it's about curly braces dear.. :) — miiiii, Nov 03 '17 at 11:44
Could you please show what you have tried so far or at least explain how the result ist supposed to look like? As was mentioned serveral times, the string you posted looks like a perfectly fine JSON. If parsed with a JSON parser, it would result in an array of arrays of `double`, whereas each inner array would have a size of 2. — Turing85, Nov 03 '17 at 11:45

score 2 · Accepted Answer · answered Nov 03 '17 at 12:18

As suggested in the comments, as the string is a valid JSON array declaration, parsing it as JSON would probably be easiest and most maintainable in the future. Using the google/gson library the code would look like this:

String string = "[[1509321600000,35166.44],[1509408000000,35224.31],[1509580800000,35234.60]]";
String[][] array = new Gson().fromJson(string, String[][].class);

Thomas Böhm · Answer 2 · 2017-11-03T12:08:49.123

There is no function provided by default, but you can do the following by using Streams (if your String has exactly that format you specified):

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

Here, you cut off the first and last two brackets (.substring(2, s.length()-2)), then split your String (.split("\\],\\["))(which results in an array of Strings of format "asdf,fdsa".

Array.stream creates a stream of that, map splits those Strings to arrays, and then you can collect them with the toArray-method.

Printing this array of arrays leads to:

1509321600000   35166.44    
1509408000000   35224.31    
1509580800000   35234.60

How can I parse a string representing an array of arrays?

2 Answers2