How to convert string array response to javascript 2D array?

Question

I am creating the following string response in JSP:

[[[1,2,3,4],[5,6,7,8]],[[9,10,11,12],[13,14,15,16]]]

and getting this response in jQuery.

But I am getting it as 1D array, I need array to be like that only

I am getting respone as

var a = "[[[1,2,3,4],[5,6,7,8]],[[9,10,11,12],[13,14,15,16]]]";

That'd be JSON data most likely, so look into using a json library, or alternatively, as a worst+last ditch effort, eval() it. — Marc B
– Marc B, Commented May 19, 2012 at 18:49
Javascript doesn't have 2D arrays... You can have arrays of arrays though, which is exactly what you're getting in your example — Philippe Leybaert
– Philippe Leybaert, Commented May 19, 2012 at 18:49
var set = eval(a) => then you can use set[0][0] to get your first array of data set[0][0][2] == 3 — web_bod
– web_bod, Commented May 19, 2012 at 18:51
Yes , eval is working fine , can we say , it will work on IE and other browsers ? — Pradeep
– Pradeep, Commented May 19, 2012 at 19:03

vol7ron · Accepted Answer · 2012-05-19 19:03:26Z

3

Two possible methods:

var arr = JSON.parse(a);
var arr = eval(a);

answered May 19, 2012 at 19:03

vol7ron

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2 Comments

Derek 朕會功夫 Over a year ago

However eval is not recommended if the string is not generated by your script itself. (I +1'd your answer though)

vol7ron Over a year ago

@Derek: yes and no. eval on the front end is a lot less troublesome then eval on the backend; however you do have to be cautious, since it is an XSS entry point. So long as your variable (a) is populated from a trusted source, your users shouldn't have to worry. The other downside of eval is the inherent performance hit, since the browser has to re-interpret the code.

Peter Olson · Accepted Answer · 2012-05-19 18:50:41Z

1

To create an arbitrarily nested array (or any object supported in JSON, for that matter) from it's string representation, you can use the JSON.parse method.

var arr = JSON.parse("[[[1,2,3,4],[5,6,7,8]],[[9,10,11,12],[13,14,15,16]]]");

answered May 19, 2012 at 18:50

Peter Olson

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5 Comments

Pradeep Over a year ago

do i need , any library to include for it to work , is it IE supported ?

Peter Olson Over a year ago

@user629804 It will work in IE8+, you can use the json2 library to add support for older browsers.

Pradeep Over a year ago

thanks ,Peter , i will go by eval approach , as it seems IE safe

Derek 朕會功夫 Over a year ago

@user629804 - You can use jQuery. JSON conversion is included there.

Amadan Over a year ago

Yeah - jQuery includes JSON2 as a shim if it is not present in the browser. Also, eval is never to be considered safe. It is kind of like having a gun with a safety on on a coat hanger in the nursery. If you take precautions it is probably safe, but enough fooling around and someone will get a foot shot off.

Amadan · Accepted Answer · 2012-05-19 18:50:15Z

0

You're getting JSON, which is a string. You need to parse it into a JavaScript object.

var object_a = JSON.parse(a);

answered May 19, 2012 at 18:50

Amadan

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Comments

thecodeparadox · Accepted Answer · 2012-05-19 18:51:45Z

0

Try this:

var data = JSON.parse(arr):

answered May 19, 2012 at 18:51

thecodeparadox

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Derek 朕會功夫 · Accepted Answer · 2012-05-19 19:18:54Z

0

Use JSON.parse:

var matrix = JSON.parse(a):

For support below IE8, use jQuery for that. (Lucky if your website already using jQuery! ;) )

answered May 19, 2012 at 19:18

Derek 朕會功夫

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