JSON parsing with multiple data

Question

Jsonlint display that this JSON object is valid:

 [{"obj":{"markers":"[{\"k\":47.040182144806664,\"B\":0.52734375},{\"k\":50.90303283111257,\"B\":10.37109375},{\"k\":52.53627304145945,\"B\":-1.7578125},{\"k\":41.77131167976406,\"B\":-6.591796875}]","path":"[[47.040182144806664,0.52734375],[50.90303283111257,10.37109375],[52.53627304145945,-1.7578125],[41.77131167976406,-6.591796875]]"}}]

I'm trying to access to markers with the k, B and path elements but it's always set to undefined. Here is my code:

 try {

       var jsonData = JSON.parse(myJson);
       console.log(jsonData.obj[0].markers[0].k);
     }
 catch (e) {
             console.error("Parsing error:", e);
           }

Can someone tell me how to access to the element of my JSON object properly? Thanks for the help.

@chazsolo No, obj is just an index of an array that I used in my MySQL query like that: $rows[] = array('obj' => $r);echo json_encode($rows); It can be 'Bob' ... — Nizar B.
– Nizar B., Commented Dec 11, 2014 at 0:04
Its because markers object is a string not an array so the value of "markers": "value here in string" — TResponse
– TResponse, Commented Dec 11, 2014 at 0:07
@loanburger What do you mean, the array is encoded into a JSON object anyway with json_encode. JSON.parse() JavaScript function works well when I get back my JSON object. The type os this JSON description is [object Object] after a JSON.parse(). Can you explain with an example please ? — Nizar B.
– Nizar B., Commented Dec 11, 2014 at 0:09
You escaped k: \"k\" is not an index - it's a value of the markers index. — orange
– orange, Commented Dec 11, 2014 at 0:14

orange · Accepted Answer · 2014-12-11 00:17:17Z

2

Something must have gone wrong in creating this string. Yes, it's valid JSON, but it has a different format than you think, because you escape control characters like " and [, ].

Try this string instead:

[
   {
      "obj":{
         "markers":[
            {
               "k":47.040182144806664,
               "B":0.52734375
            },
            {
               "k":50.90303283111257,
               "B":10.37109375
            },
            {
               "k":52.53627304145945,
               "B":-1.7578125
            },
            {
               "k":41.77131167976406,
               "B":-6.591796875
            }
         ],
         "path":[
            [
               47.040182144806664,
               0.52734375
            ],
            [
               50.90303283111257,
               10.37109375
            ],
            [
               52.53627304145945,
               -1.7578125
            ],
            [
               41.77131167976406,
               -6.591796875
            ]
         ]
      }
   }
]

as opposed to your string:

[
   {
      "obj":{
         "markers":"[{\"k\":47.040182144806664,\"B\":0.52734375},{\"k\":50.90303283111257,\"B\":10.37109375},{\"k\":52.53627304145945,\"B\":-1.7578125},{\"k\":41.77131167976406,\"B\":-6.591796875}]",
         "path":"[[47.040182144806664,0.52734375],[50.90303283111257,10.37109375],[52.53627304145945,-1.7578125],[41.77131167976406,-6.591796875]]"
      }
   }
]

answered Dec 11, 2014 at 0:17

orange

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3 Comments

Nizar B. Over a year ago

Maybe your JSON description is more well formed, I just tested it but still undefined when I'm trying to access to the element after JSON.parse().

orange Over a year ago

How did you access the value? To obtain the first 47.040182144806664, I do jsonData[0].obj.markers[0].k. Did you do the same? This works fine for me...

Nizar B. Over a year ago

Sorry your version is right, now it's better, thank you!

TResponse · Accepted Answer · 2014-12-11 00:12:42Z

0

You have two issues from what I can tell:

One, yes it is valid Json but the marker and path object values are enclosed in string quotes:

"markers":"[{\"k\":47.040182144806664,\"B\":0.52734375},{\"k\":50.90303283111257,\"B\":10.37109375},{\"k\":52.53627304145945,\"B\":-1.7578125},{\"k\":41.77131167976406,\"B\":-6.591796875}]",
"path":"[[47.040182144806664,0.52734375],[50.90303283111257,10.37109375],[52.53627304145945,-1.7578125],[41.77131167976406,-6.591796875]]"

what you rather want is:

"markers":[{"k":47.040182144806664,"B":0.52734375},{"k":50.90303283111257,"B":10.37109375},{"k":52.53627304145945,"B":-1.7578125},{"k":41.77131167976406,"B":-6.591796875}],

"path":[[47.040182144806664,0.52734375],[50.90303283111257,10.37109375],[52.53627304145945,-1.7578125],[41.77131167976406,-6.591796875]]

But given the above, also not escape the k and b object names for markers \"k\" should be "k":

So the completed edited JSON would look like this:

[{"obj":{"markers":[{"k":47.040182144806664,"B":0.52734375},{"k":50.90303283111257,"B":10.37109375},{"k":52.53627304145945,"B":-1.7578125},{"k":41.77131167976406,"B":-6.591796875}],"path":[[47.040182144806664,0.52734375],[50.90303283111257,10.37109375],[52.53627304145945,-1.7578125],[41.77131167976406,-6.591796875]]}}]

answered Dec 11, 2014 at 0:12

TResponse

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2 Comments

Nizar B. Over a year ago

You're markers and path still double quoted in your answer ?

TResponse Over a year ago

Yes that's just the object names but the values are not in quotes

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