Javascript获取数组中键的所有值？

Question

如何在没有 jQuery的数组中获取键的所有值？

var species = [{"code_name":"b","public_name":"a"},{"code_name":"d","public_name":"c"},{"code_name":"f","public_name":"e"}];

var speciesVals = Object.keys(species).map(function (val, key) {
    return val;
});

结果：

[ '0',
  '1',
  '2',
  '_atomics',
  '_parent',
  '_cast',
  '_markModified',
  '_registerAtomic',
  '$__getAtomics',
  'hasAtomics',
  '_mapCast',
  'push',
  'nonAtomicPush',
  '$pop',
  'pop',
  '$shift',
  'shift',
  'pull',
  'splice',
  'unshift',
  'sort',
  'addToSet',
  'set',
  'toObject',
  'inspect',
  'indexOf',
  'remove',
  '_path',
  'isMongooseArray',
  'validators',
  '_schema' ]

但我在追求：

["code_name":["b", "d", "d"], "public_name":["a", "c", "e"]

有可能吗？

修改

这个怎么样：

[{"code_name":["b", "d", "d"]}, {"public_name":["a", "c", "e"}]

Answer 1

使用JavaScript Array#reduce 方法。

＆＃13;

＆＃13;

var species = [{
  "code_name": "b",
  "public_name": "a"
}, {
  "code_name": "d",
  "public_name": "c"
}, {
  "code_name": "f",
  "public_name": "e"
}];

var temp = species.reduce(function(res, v) {
  // iterate over object(array element)
  Object.keys(v).forEach(function(k) {
    // define property as array if not defined
    res[k] = res[k] || [];
    // push the value to prefered array
    res[k].push(v[k]);
  });
  // return the updated object
  return res;
  // define the initial value as object to hold the result
}, {});

// now create your expected result
var speciesVals = Object.keys(temp) // get all property names
  .map(function(v) { //iterate over them to generate the result array
    var obj = {}; // create object for 
    obj[v] = temp[v]; // add property
    return obj; // return object (which is the new array element)
  });


console.log(speciesVals);

＆＃13;

＆＃13;

＆＃13;

Answer 2

当然有可能。如果对象键对于数组中的每个对象都相同，则可以执行以下操作：

var species = [{"code_name":"b","public_name":"a"},{"code_name":"d","public_name":"c"},{"code_name":"f","public_name":"e"}];
var res = {code_name: [], public_name: []};
   
for(var i = 0; i < species.length; i++){
    res.code_name.push(species[i].code_name);
    res.public_name.push(species[i].public_name);
}

console.log(res);

修改

获取对象数组：

var species = [{"code_name":"b","public_name":"a"},{"code_name":"d","public_name":"c"},{"code_name":"f","public_name":"e"}];
var res = [{code_name: []}, {public_name: []}];
   
for(var i = 0; i < species.length; i++){
    res[0].code_name.push(species[i].code_name);
    res[1].public_name.push(species[i].public_name);
}

console.log(res);

Answer 3

我建议为属性使用固定数组，因为您只需要'code_name和public_name。

var species = [{ "code_name": "b", "public_name": "a" }, { "code_name": "d", "public_name": "c" }, { "code_name": "f", "public_name": "e" }],
    speciesVals = {};

species.forEach(function (a) {
    ['code_name', 'public_name'].forEach(function (k) {
        speciesVals[k] = speciesVals[k] || [];
        speciesVals[k].push(a[k]);
    });
});

console.log(speciesVals);