JSON get value of a param of a object whose object name is random

Question

I am very new to JSON, have been pestered to get this done.I have to get the value of "extract" as in the given diagram. This diagram is a object diagram of a json. The value 21721040 can be random, thus I do not know the name of the object whose one of the members I seek.

Thus I cannot do something like

query.pages.21721040.extract

enter image description here

So how can I get the value of "extract"?

Out of curiosity should the object whose name is a numeral create an error when I try to access one of its members? Or they just work? For example in this case one of the object's name is "-1".

enter image description here

If I try to access the value "url" after parsing in JS like this:

query.pages.-1.imageinfo.0.url

Will it throw an error?

Do you know the id beforehand?

Ja͢ck
– Ja͢ck

2014-07-01 04:32:54 +00:00
Commented Jul 1, 2014 at 4:32 — Ja͢ck
– Ja͢ck, Commented Jul 1, 2014 at 4:32
try query.pages["-1"].imageinfo[0].url

Kamrul
– Kamrul

2014-07-01 04:33:37 +00:00
Commented Jul 1, 2014 at 4:33 — Kamrul
– Kamrul, Commented Jul 1, 2014 at 4:33
Nope. Can only be known at runtime.

Ashwin Singh
– Ashwin Singh

2014-07-01 04:33:40 +00:00
Commented Jul 1, 2014 at 4:33 — Ashwin Singh
– Ashwin Singh, Commented Jul 1, 2014 at 4:33
Is this data coming from Wikipedia API by any chance?

Ja͢ck
– Ja͢ck

2014-07-01 04:49:56 +00:00
Commented Jul 1, 2014 at 4:49 — Ja͢ck
– Ja͢ck, Commented Jul 1, 2014 at 4:49
@Jack Yes it is being fetched from their API.

Ashwin Singh
– Ashwin Singh

2014-07-01 05:01:21 +00:00
Commented Jul 1, 2014 at 5:01 — Ashwin Singh
– Ashwin Singh, Commented Jul 1, 2014 at 5:01

abdulbasit · Accepted Answer · 2014-07-01 04:41:48Z

1

try this :

query.pages[Object.keys(query.pages)[0]].extract

answered Jul 1, 2014 at 4:41

abdulbasit

1,9361 gold badge15 silver badges17 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

Ashwin Singh Over a year ago

Javascript's indexes for json are mashed up. Can you comment on that, will your method always return the right value?

Evan Darwin Over a year ago

It's different than my answer due to Object.keys() returning an actual array and not an object.

Kamrul · Accepted Answer · 2014-07-01 04:43:00Z

1

try query.pages["-1"].imageinfo[0].url. actually all the fields can be considered as string. so you can write query["pages"]["-1"]["imageinfo"]["0"]["url"]

if you do not know the key, use Object.keys() to find out the keys associated to that object. this key can be any key belong to the object or the object it has been inherited from. to find out only the object's own key user hasOwnProperty

answered Jul 1, 2014 at 4:43

Kamrul

7,3213 gold badges34 silver badges31 bronze badges

Comments

Ja͢ck · Accepted Answer · 2014-07-01 05:04:04Z

1

If you don't know the property name, you can iterate over the properties on the object yourself:

for (var key in query.pages) {
    if (query.pages.hasOwnProperty(key)) {
        console.log(query.pages[key].extract);
    }
}

Alternatively, you can use the relatively modern Object.keys() to obtain an array of keys that the object has.

edited Jul 1, 2014 at 5:04

answered Jul 1, 2014 at 4:35

Ja͢ck

174k39 gold badges269 silver badges317 bronze badges

7 Comments

Ashwin Singh Over a year ago

Is it a property or a child object? From the very limited knowledge I have it looks like an object as it contains key:value pairs and its not itself a key value pair.

Ashwin Singh Over a year ago

Can it be modified to register only the property containing "extract"? Or I need to check for empty values?

Ja͢ck Over a year ago

@AshwinSingh Is what a property or child object? I don't think property and child object are mutually exclusive terms.

Ja͢ck Over a year ago

@AshwinSingh I don't understand what you mean by "register the property containing 'extract'"; could you clarify?

Ashwin Singh Over a year ago

I mean log. I am under the impression that your method will log null values for items not containing any "extract" member. Can the loop be done for a simple straight-forward access as there are cases where there can be a lot of keys..

|

Collectives™ on Stack Overflow

JSON get value of a param of a object whose object name is random

3 Answers 3

2 Comments

Comments

7 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

2 Comments

Comments

7 Comments

Your Answer

Sign up or log in

Post as a guest

Related