sum two selected keys separately from array of objects and divide the result-CodePudding

I want to sum a and b separately and divide their result by b/a .

{"a":10,"b":20,"c":29,"d":0},
{"a":25,"b":0,"c":9.13,"d":11},
{"a":0,"b":15.5,"c":86,"d":0},
{"a":21.2,"b":0,"c":34,"d":0}]

a=20 10 25 0 21 = 76

b=25.25 20 0 15.5 0 = 60.75

b/a = 60.75/76 = 0.799

CodePudding user response：

This should do it:

let elements =[{"a":10,"b":20,"c":29,"d":0},
{"a":25,"b":0,"c":9.13,"d":11},
{"a":0,"b":15.5,"c":86,"d":0},
{"a":21.2,"b":0,"c":34,"d":0}];
let result={}
for (let el of elements){
    for (let k in el){
        result[k]=(result[k]||0) el[k];
    }
}
console.log(result.b / result.a)

CodePudding user response：

let ar = [
  {"a":10,"b":20,"c":29,"d":0}, 
  {"a":25,"b":0,"c":9.13,"d":11}, 
  {"a":0,"b":15.5,"c":86,"d":0}, 
  {"a":21.2,"b":0,"c":34,"d":0}
];
const ab = ar.reduce((s,c) => ({a: s.a   c.a, b: s.b   c.b}), {a: 0, b: 0});
console.log(ab.b / ab.a);

you can use reduce if you don't want to use external vars.

CodePudding user response：

Use map to go through the array of objects and sum the elements along the way.

let sumA;
let sumB;
Arr.map((i) => {
  sumA  = i.a;
  sumB  = i.b;
});
console.log(sumA)
console.log(sumB)
console.log(sumB/sumA)

CodePudding user response：

var obj = [{"a":10,"b":20,"c":29,"d":0},
{"a":25,"b":0,"c":9.13,"d":11},
{"a":0,"b":15.5,"c":86,"d":0},
{"a":21.2,"b":0,"c":34,"d":0}];

// better practice to use map/reduce

var sum = 0;

for (var i = 0; i < Object.values(obj).length; i  ) {
  sum  = Object.values(obj)[i]["a"];
}

console.log('sum', sum);

var sum2 = 0;

for (var t = 0; t < Object.values(obj).length; t  ) {
  sum2  = Object.values(obj)[t]["b"];
}

console.log('sum2', sum2);

console.log('divided', sum / sum2);