遍历Javascript对象返回值的总和

Question

What I'm trying to do is loop through an object getting the total times that each candidate appears and print that to the page.

I've have been racking my head on this one. I'm new to javascript and working with objects is something very new to me.

Thank you for the help!

 var entry = [ { candidate : "guy1", rank : 1, state : "AK", vote_count : "2" }, { candidate : "guy2", rank : 1, state : "MI", vote_count : "3" }, { candidate : "guy3", rank : 1, state : "AK", vote_count : "5" }, { candidate : "guy2", rank : 1, state : "AL", vote_count : "4" }, { candidate : "guy2", rank : 1, state : "FL", vote_count : "9" }, { candidate : "guy1", rank : 1, state : "MN", vote_count : "7" } ]; for ( var i = 0, l = entry.canidate.length; i < l; i++ ) { guy1 += entry.canidate[i]; } console.log(guy1); 

Answer 1

You could use an object with the candidates as key and count the votes.

 var entry = [{ candidate: "guy1", rank: 1, state: "AK", vote_count: "2" }, { candidate: "guy2", rank: 1, state: "MI", vote_count: "3" }, { candidate: "guy3", rank: 1, state: "AK", vote_count: "5" }, { candidate: "guy2", rank: 1, state: "AL", vote_count: "4" }, { candidate: "guy2", rank: 1, state: "FL", vote_count: "9" }, { candidate: "guy1", rank: 1, state: "MN", vote_count: "7" }], count = {}; entry.forEach(function (a) { count[a.candidate] = (count[a.candidate] || 0) + +a.vote_count; }); console.log(count); 

Answer 2

You can create a new object with the summation of votes by candidates like this:

https://jsfiddle.net/he58xsb8/

var entry = [
  {
    candidate : "guy1",
    rank : 1,
    state : "AK",
    vote_count : "2"
  },
  {
    candidate : "guy2",
    rank : 1,
    state : "MI",
    vote_count : "3"
  },
  {
    candidate : "guy3",
    rank : 1,
    state : "AK",
    vote_count : "5"
  },
  {
    candidate : "guy2",
    rank : 1,
    state : "AL",
    vote_count : "4"
  },
  {
    candidate : "guy2",
    rank : 1,
    state : "FL",
    vote_count : "9"
  },
  {
    candidate : "guy1",
    rank : 1,
    state : "MN",
    vote_count : "7"
  }
];

var voteByCandidate = {};
for ( var i = 0; i < entry.length; i++ ) {
    var result = entry[i];
    if (!voteByCandidate[result.candidate]) {
        voteByCandidate[result.candidate] = 0;
    }
    voteByCandidate[result.candidate] += result.vote_count * 1; // Convert to number.
}

console.log(voteByCandidate);

Answer 3

You can create a candidateMap and loop entry array .for each same candidate increment the key in the map.

var candidateMap = {};

entry.forEach( function(candidate) {
   candidateMap[candidate.candidate] = candidateMap[candidate.candidate] || 0;
candidateMap[candidate.candidate] += 1;
}); 

Answer 4

You can easily do this with reduce:

 var entries = [{ candidate: "guy1", rank: 1, state: "AK", vote_count: "2" }, { candidate: "guy2", rank: 1, state: "MI", vote_count: "3" }, { candidate: "guy3", rank: 1, state: "AK", vote_count: "5" }, { candidate: "guy2", rank: 1, state: "AL", vote_count: "4" }, { candidate: "guy2", rank: 1, state: "FL", vote_count: "9" }, { candidate: "guy1", rank: 1, state: "MN", vote_count: "7" }]; var result = entries.reduce(function(r, c) { r[c.candidate] = (r[c.candidate] || 0) + parseInt(c.vote_count); return r; }, {}); console.log(result); 

Answer 5

I'm looking to get the total times that each candidate appears

You can use array filter to filter the candidates then reduce to count the number of occurrence of each candidate

var _filter=[];
entry.filter(function(item){
  _filter.push(item.candidate)
})

var _reducedArray =_filter.reduce(function(prev,next){
        prev[next] = (prev[next] + 1) || 1;
        return prev;
    },{});

console.log(_reducedArray);

JSFIDDLE

Answer 6

This might be what you need:

const votes = {};
entry.foraEach(item => {
    if(!votes.hasOwnProperty(item.candidate)) {
        votes[item.candidate] = +item.vote_count;
    } else votes[item.candidate] += +item.vote_count;
});

You will have all the candidates and votes inside the votes object.

Answer 7

 var entry = [ { candidate : "guy1", rank : 1, state : "AK", vote_count : "2" }, { candidate : "guy2", rank : 1, state : "MI", vote_count : "3" }, { candidate : "guy3", rank : 1, state : "AK", vote_count : "5" }, { candidate : "guy2", rank : 1, state : "AL", vote_count : "4" }, { candidate : "guy2", rank : 1, state : "FL", vote_count : "9" }, { candidate : "guy1", rank : 1, state : "MN", vote_count : "7" } ]; function getCandidateTimes(entry, candidateName){ var appearTimes = 0; for (var i=0, len = entry.length; i < len; i++){ if(entry[i].candidate == candidateName){ appearTimes++; } } return appearTimes; } var guy1AppearTimes = getCandidateTimes(entry, 'guy1'); console.log('guy1 appears ' + guy1AppearTimes + ' times!'); var guy2AppearTimes = getCandidateTimes(entry, 'guy2'); console.log('guy2 appears ' + guy2AppearTimes + ' times!'); //and so on.......