CODEWITHSUNDEEP
javascriptjqueryjsonobject
scttcrry
scttcrry

Reputation: 69

Using Value from Option to get data from JSON

friends! I've got a json file, a .js file, and some html.

I can read the data from the json file in the js file just fine, and it's outputting to the console.

So I have a dropdown with all 50 states, and the values are the states abbreviations. Each state was 6 different values like such:

"AK": {
  "I": 0,
  "II": 0,
  "III": 0,
  "IV": 0,
  "V": 0,
  "VI": 0
 }

I can console the data as such: data.AK.II and it is fine.

I'm having issues achieving this: data.(the value of the option selected).II

   $('select#input_56_3').on('change', function () {
var thisValue = $('select#input_56_3 option:selected').val();
var newValue = data.thisValue.I;
console.log('newValue = ' + newValue);
  });

This is the error I'm getting, so 'thisValue' is coming across undefined.

Uncaught TypeError: Cannot read property 'I' of undefined

Should I be converting it some way? I think I've been staring at this too long.

Upvotes: 1

Views: 225

Answers (2)

hygull
hygull

Reputation: 8740

Change data.thisValue.II to data[thisValue].II, it will work.

  • Bracket notation is basically used when there's a space in key names e.g. "full name" etc.
  • Do notation is used if you are directly trying to access the values in object. If d = {k: 1} then d.k and d[k] both are fine. d = {"k v": 1} then only d["k v"] will work.
> data = {
...     "AK": {
.....         "I": 0,
.....         "II": 0,
.....         "III": 0,
.....         "IV": 0,
.....         "V": 0,
.....         "VI": 0
.....     }
... }
{ AK: { I: 0, II: 0, III: 0, IV: 0, V: 0, VI: 0 } }
> 
> thisValue = "AK"
'AK'
> 
> data[thisValue].I
0
> data[thisValue].II
0
>

The following will throw an exception (error).

> data.thisValue.II
Thrown:
TypeError: Cannot read property 'II' of undefined
>

Upvotes: 1

Jack Bashford
Jack Bashford

Reputation: 44087

Use square bracket notation:

var newValue = data[thisValue].I;

Upvotes: 1

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