JavaScript regex to match numbers in array

Question

I have the following text:

 {"status": "ok","data": {"grpd": 0,"obj": 073741824,"objInst": 0,"no": null,"values": [3.523422,0,-323123123,3.423,9223372036854775807,0,"test 123.32",0,0,"",0,0]}}

I need to match and place quotes around the numbers in the array "values" so its result should be:

 {"status": "ok","data": {"grpd": 0,"obj": 073741824,"objInst": 0,"no": null,"values": ["3.523422","0","-323123123","3.423","9223372036854775807","0","test 123.32","0","0","","0","0"]}}

The numbers can be with float point, negative and normal.

Use a JSON parser. If I could comment this a dozen times, I would. You might use a regex along the way, but regex should not be the primary solution here I think. — Tim Biegeleisen
– Tim Biegeleisen, Commented Sep 19, 2017 at 6:08
Why make numbers into strings though? If there's one thing I've learned it's let primitive types retain their native type. — Sterling Archer
– Sterling Archer, Commented Sep 19, 2017 at 6:09
Most likely you are taking the wrong approach and no need to convert numbers to strings. Since they are numbers... — marekful
– marekful, Commented Sep 19, 2017 at 6:11
I am converting them because I need to work with big numbers, which JS doesn't support, I only need to get these values and place them on the page. Big number is this: 9223372036854775807. Try to place it to your console like a number. If there is better way to do this I will be happy to use it but I don't know it. So I am converting them to string and then parse them with JSON parser. — Milen Grigorov
– Milen Grigorov, Commented Sep 19, 2017 at 6:15
how do you generate this JSON? why don't you make obj.data.values an String[] before/when building this JSON? Is there really a problem with these numbers being numbers and not strings, when you only want to place them on the page, as you said? So many questions, just to avoid this hack — Thomas
– Thomas, Commented Sep 19, 2017 at 6:25

JosephC · Accepted Answer · 2017-09-19 06:17:43Z

1

You can loop through the data and convert it into string as shown below:

var data =  {"status": "ok","data": {"grpd": 0,"obj": 073741824,"objInst": 0,"no": null,"values": [3.523422,0,-323123123,3.423,9223372036854775807,0,"test 123.32",0,0,"",0,0]}}

var values = [];

for (var i = 0 ; i < data.data.values.length ; i ++) {
    values.push(String(data.data.values[i]));
}

data.data.values = values;

console.log(data);

answered Sep 19, 2017 at 6:17

JosephC

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Comments

Ankit Agarwal · Accepted Answer · 2017-09-19 06:19:03Z

1

You simply have a loop to check the value is a number or float value and convert to string.

var obj1 = {"status": "ok","data": {"grpd": 0,"obj": 073741824,"objInst": 0,"no": null,"values": [3.523422,0,-323123123,3.423,9223372036854775807,0,"test 123.32",0,0,"",0,0]}};

obj1.data.values.forEach(function(value, index, theArray) {
 if (!isNaN(value) || value.toString().indexOf('.') != -1)
    {
       theArray[index] = value.toString();
    }
});

console.log(obj1);

answered Sep 19, 2017 at 6:19

Ankit Agarwal

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3 Comments

Milen Grigorov Over a year ago

Thanks for the answer but the big numbers will be lost with this method.

Ankit Agarwal Over a year ago

Javascript does not support large numbers as they truncate them so to preserve them you need to send those as a string from server itself

Milen Grigorov Over a year ago

Yes, I know that and that's why I ask the question. But I can't change the server, this is server on specific device, and can't be changed like that.

Mustofa Rizwan · Accepted Answer · 2017-09-19 07:10:36Z

1

If you really need to do it by regex then you may try this.

const regex = /(-?\d+(\.\d+)?)(?![^,]*")/g;
const str = `{"status": "ok","data": {"grpd": 0,"obj": 073741824,"objInst": 0,"no": null,"values": [3.523422,0,-323123123,3.423,9223372036854775807,0,"test 123.32",0,0,"",0,0]}}`;
const subst = `"$1"`;

const result = str.replace(regex, subst);

console.log(result);

Regex Demo

UPDATE AS per the comment:

(\:\s*|,|\[|\{)\s*(-?\d+(?:\.\d+)?)(?=[,\]\}])

Demo 2

const regex = /(\:\s*|,|\[|\{)\s*(-?\d+(?:\.\d+)?)(?=[,\]\}])/g;
const str = `{"status": "ok","data": {"grpd": 0,"obj": 073741824,"objInst": 0,"no": null,"values": [3.523422,0,-323123123,3.423,"test 123.3,2",0,"test 123.32",0,0,"","adsa22s22",0]}}`;
const subst = `$1"$2"`;


const result = str.replace(regex, subst);

console.log(result);

edited Sep 19, 2017 at 7:10

answered Sep 19, 2017 at 6:16

Mustofa Rizwan

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9 Comments

skirtle Over a year ago

I don't believe this works for the "test 123.32" example found in the original test data.

Milen Grigorov Over a year ago

Just one more question, if I have ","adsa22s22"," it will match 2 also, how can I escape them matching?

Mustofa Rizwan Over a year ago

@MilenGrigorov does that answer your problem now ?

skirtle Over a year ago

I can't speak as to the OP's requirements but something like "test 123.32, 16" would be very difficult to handle correctly using a RegExp.

Milen Grigorov Over a year ago

Oh @skirtle just gave good example, now I am wondering if it possible to catch every single case.

|

skirtle · Accepted Answer · 2017-09-19 07:11:31Z

If you really can't change the original JSON to use strings for numbers that aren't within the range supported by JS then you could use something like this:

var json = '{"status": "ok","data": {"grpd": 0,"obj": 073741824,"objInst": 0,"no": null,"values": [3.523422,0,-323123123,3.423,9223372036854775807,0,"test 123.32",0,0,"",0,0, "test \\u0022 123", "test \\" 123"]}}';

var inString = false;
var inNumber = false;
var out = '';

for (var index = 0, len = json.length ; index < len ; ++index) {
    var chr = json.charAt(index);
    
    switch (chr) {
        case '"':
            inString = !inString;
            break;
            
        case '\\':
            out += chr + json.charAt(index + 1);
            ++index;
            continue;
            
        case '-':
        case '.':
        case '0':
        case '1':
        case '2':
        case '3':
        case '4':
        case '5':
        case '6':
        case '7':
        case '8':
        case '9':
            if (!inString && !inNumber) {
                out += '"';
                inNumber = true;
            }
            
            break;
            
        default:
            if (inNumber) {
                inNumber = false;
                out += '"';
            }
    }
    
    out += chr;
}

console.log(out);

Handling the numbers in strings is too tricky using a RegExp so I haven't even tried. I've assumed the JSON is valid... my crude parser won't cope at all well if it isn't. I've also ignored the 7e5 notation for numbers, that would need a bit of extra work to avoid matching the e in true.

I haven't explicitly targeted the array values but it could be adapted accordingly. How exactly you'd do that depends on whether you want to cope with generic JSON or something a little more targeted to your exact format. You might only put quotes around numbers once they get to a certain length, for example. That would be easy to add by tracking the exact index that a number starts at rather than just using an isNumber flag.

If I was going to use something like this in production I would write a shed load of unit tests to ensure it really does work.

Arsen Ghazaryan · Accepted Answer · 2017-09-19 06:19:05Z

0

let obj = JSON.parse(response);
obj.values = obj.values.map(item => typeof item === 'number' ? '"'+item+'"');
console.log(JSON.stringify(obj));

or with es5

obj.values = obj.values.map(function(item) {
  return typeof item === 'number' ? '"'+item+'"';
}

or instead of typeof item === 'number' you can use ! isNaN(item)

answered Sep 19, 2017 at 6:19

Arsen Ghazaryan

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1 Comment

Milen Grigorov Over a year ago

When I hit the first line "let obj = JSON.parse(response);" I lost the big numbers because JS doesn't support them. Thanks anyway, some guys above give me good regex.

gurvinder372 · Accepted Answer · 2017-09-19 06:53:29Z

0

Parse them into a JS object first

var obj = JSON.parse( jsonString );

then

obj.data.values = obj.data.values.map( function( item ){ return !isNaN( item ) ? String( item ) : item; });

Convert it back to JSON string format

jsonString  = JSON.stringify( obj );

However, if the numerals are beyond what javascript objects can take, then use this regex based solution

var str = '{"status": "ok","data": {"grpd": 0,"obj": 073741824,"objInst": 0,"no": null,"values": [3.523422,0,-323123123,3.423,9223372036854775807,0,"test 123.32",0,0,"",0,0]}}';

str = str.replace(/[,|\[](\-){0,1}\d+(\.\d+)*(?=[,|\]])/g, function(match){ var firstChar = match.charAt(0); match = match.substring( 1 ); return firstChar + "\"" + match + "\"" ; });

console.log( str );

edited Sep 19, 2017 at 6:53

answered Sep 19, 2017 at 6:13

gurvinder372

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3 Comments

Milen Grigorov Over a year ago

I am converting them because I need to work with big numbers, which JS doesn't support, I only need to get these values and place them on the page. Big number is this: 9223372036854775807. Try to place it to your console like a number. If there is better way to do this I will be happy to use it but I don't know it. So I am converting them to string and then parse them with JSON parser.

gurvinder372 Over a year ago

@MilenGrigorov I got it now, parsing to json/number approach won't work.

Milen Grigorov Over a year ago

it works good now, thank you but I already accepted the answer by Rizwan Tuman.

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