CODEWITHSUNDEEP
javascriptd3.js
learner
learner

Reputation: 1023

How should I use map to get back some values of an object when the key are user input

I have data as shown below:

0: Object { IG: "Low income", FLFPR: 47.00099945, lnGDP: 7.496679918, … }
​​
1: Object { IG: "Upper middle income", FLFPR: 47.67599869, lnGDP: 9.302921813, … }
​​
2: Object { IG: "Upper middle income", FLFPR: 15.18999958, lnGDP: 9.526954146, … }
​​
3: Object { IG: "Lower middle income", FLFPR: 75.47899628, lnGDP: 8.802498179, … }
​​
4: Object { IG: "High income", FLFPR: 47.82500076, lnGDP: 9.858328453, … }
​​
5: Object { IG: "Upper middle income", FLFPR: 51.16600037, lnGDP: 9.011393414, … }

I need only say IG and FLFPR from each object. Also, I do not know the values IG and FLFPR. They are user inputs. For example, inputx = IG and inputy = FLFPR.

I tried using map but I couldn't get it to work. I know the below code is incorrect, but intutively this is what I need.

xydata = data.map(item => {x: item.inputx, y: item.inputy});

Is it right to use map in this context ?

Edit:

    dat = [{x: 8, y: 3, z:5},{x: 2, y: 10, z:5},{x: 11, y: 3, z:5},{x: 6, y: 6, z:5},{x: 5, y: 8, z:5}]
    xText = 'x'
    yText = 'y'  
    xydata = dat.map(item => ({x: item.[xText], y: item.[yText]}));

Upvotes: 0

Views: 36

Answers (2)

junvar
junvar

Reputation: 11584

You can use [] to access object properties dynamically.

let x = {dog: 3, cat: 4, key: 5};
let key = 'dog';

console.log(x.key); // 5
console.log(x['key']); // also 5
console.log(x[key]); // 3

In your case:

xydata = data.map(item => ({x: item[inputx], y: item[inputy]}));

Similarly, you can use [] when creating objects with dynamic property names.

let key = 'dog';
let x = {
  cat: 5,
  [key]: 6,
  key: 7,
};

console.log(x.key); // 7
console.log(x.dog); // 6

Upvotes: 1

Code Maniac
Code Maniac

Reputation: 37745

To access object values knowing key name is enough, You need to use proper key names to access values

change to this

xydata = data.map(item => ({x: item.IG, y: item.FLFPR}));

Upvotes: 1

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