不使用 For 循环处理任何数组

Question

我想在不使用FOR循环的情况下动态实现输出。输入是多个对象的数组。var input = [  {    "name": "Siner1",    "RTime": 40,    "FTime": 30  },  {    "name": "Siner2",    "RTime": 50,    "FTime": 60  }]var output = [  {    "RTime": {      "Siner1": 40,      "Siner2": 50    },    "FTime": {      "Siner1": 30,      "Siner2": 60    }  }]//console.log(input)console.log(output);有人可以帮助我吗？

Answer 1

方法一

var input = [

  {

    "name": "Siner1",

    "RTime": 40,

    "FTime": 30

  },

  {

    "name": "Siner2",

    "RTime": 50,

    "FTime": 60

  }

]

var output = input.reduce(function(initial,next){

   initial["RTime"][next["name"]]=(initial["RTime"][next["name"]] || 0 ) + next["RTime"];

   initial["FTime"][next["name"]]=(initial["FTime"][next["name"]] || 0 ) + next["FTime"];

   return initial;

},{"RTime":{},"FTime":{}});

console.log(output)

方法二

如果您想要聚合其他键或值

var input = [

  {

    "name": "Siner1",

    "RTime": 40,

    "FTime": 30

  },

  {

    "name": "Siner2",

    "RTime": 50,

    "FTime": 60

  }

]

var keys = ['RTime','FTime'];

output=input.reduce(function(initial,next){

   keys.map(function(key){

        initial[key][next["name"]]=(initial[key][next["name"]] || 0 ) + next[key];

   });

   return initial;

},keys.reduce(function(data,key){

   data[key]={};

   return data;

},{}));

console.log(output)

Answer 2

提供的通用方法基于Array.prototype.reduce. 由于它使用accumulator其回调函数的参数作为可配置项，collector因此它完全不知道任何给定列表的任何已处理项目的键。只需要提供已处理项目的（源）键值，然后作为新分组键值的目标键...

function restructureKeysAndValues(collector, item) {

  const {

    keyOfTargetValue,

    registry,

    index,

    list

  } = collector;

  const targetKey = item[keyOfTargetValue];

  Object.entries(item).forEach(([key, value]) => {

    if (key !== keyOfTargetValue) {

      let keyGroup = registry[key];

      if (!keyGroup) {

        keyGroup = registry[key] = { [key]: {} };

        Object.assign(index, keyGroup);

        list.push(keyGroup);

      }

      keyGroup[key][targetKey] = value;

    }

  });

  return collector;

}

console.log('a list of group objects ...', [{

    "name": "Siner1",

    "RTime": 40,

    "FTime": 30

  }, {

    "name": "Siner2",

    "RTime": 50,

    "FTime": 60

  }].reduce(restructureKeysAndValues, {

    keyOfTargetValue: 'name',

    registry: {}, // - for internal tracking

    index: {},    // - for external use, output as map/index. 

    list: []      // - for external use, output as array/list.

  }).list

);

console.log('a single grouped object ...', [{

    "name": "Siner1",

    "RTime": 40,

    "FTime": 30

  }, {

    "name": "Siner2",

    "RTime": 50,

    "FTime": 60

  }].reduce(restructureKeysAndValues, {

    keyOfTargetValue: 'name',

    registry: {}, // - for internal tracking

    index: {},    // - for external use, output as map/index. 

    list: []      // - for external use, output as array/list.

  }).index

);

console.log('a list of group objects ...', [{

    "name": "Siner1",

    "RTime": 40,

    "FTime": 30,

    "CTime": 70,

    "ATime": 90

  }, {

    "name": "Siner2",

    "RTime": 50,

    "FTime": 60,

    "CTime": 30,

    "ATime": 40

  }, {

    "name": "Siner3",

    "RTime": 90,

    "FTime": 20,

    "CTime": 10,

    "ATime": 20

  }].reduce(restructureKeysAndValues, {

    keyOfTargetValue: 'name',

    registry: {}, // - for internal tracking

    index: {},    // - for external use, output as map/index. 

    list: []      // - for external use, output as array/list.

  }).list

);

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