Parse string to array

Question

Is there by any chance a built-in javascript function that parses:

var string = '[2,1,-4]';
var multiString = '[[-3,2,-1][2,-3,2][1,-1,3]]';

to

var array = [2,1,-4];
var multiArray = [[-3,2,-1],[2,-3,2],[1,-1,3]];

or do I have to write a custom function for this?

• VisioN: You have a syntax error in your resulting multiarray.
• putvande: How did you end up with strings and not Arrays?
• deceze: That could almost be valid JSON, but is not...
• lephleg: @putvande read from file

Answer 1

Assuming your correct your multiString to the correct format
(ie. '[[-3,2,-1],[2,-3,2],[1,-1,3]]')

Then yes.

array = JSON.parse(string);
multiArray = JSON.parse(multiString);

• lephleg: So if I can change a bit the initial string format is possible.. hmm Thanks!
• Batu.Khan: He can do JSON.parse(multiString.replace(/\]\[/g,"],[")); if necessary

Answer 2

For completeness, you can use eval:

var s = '[1,2,3]';
var a = eval(s);

however if the string is valid JSON, then as Niet suggested, JSON.parse is a much better solution.

Answer 3

If you want to do this on your own, it can be done using substring and split. A possible solution could look like this:

var multiString = '[[-3,2,-1][2,-3,2][1,-1,3]]';
var string = '[2,1,-4]'; 
function parse(input) {
 var s = input;
 // remove leading [ and trailing ] if present
 if (input[0] == "[") {
 s = input.substring(0, input.length);
 }
 if (input[input.length] == "]") {
 s = s.substring(input.length-1, 1);
 }
 // create an arrray, splitting on every ,
 var items = s.split(",");
 return items;
}
// items is now an array holding 2,-1,4
var items = parse(string);

You can then split the bigger string into smaller chunks and apply the function to each part using array.map:

function parseAOfA(input) {
 var s = input.substring(0, input.length).substring(input.length-1, 1);
 s = s.substring(0, s.length).substring(s.length-1, 1);
 s = s.split("][");
 var items = s.map(parse);
 return items;
}
var items = parseAOfA(multiString);

• putvande: This doesn't work for the multiString '[[-3,2,-1],[2,-3,2],[1,-1,3]]'
• keenthinker: I am extending my answer right now to address this part of the question too.
• lephleg: Yes, that's the "hard" way to go. I was going to come to this if something like JSON.parse() wouldn't work. Thanks for your time - downvote neutralised.
• keenthinker: @putvande i have updated my code, so my solution now works for both inputs.