Question

我正在玩reactjs并且在处理对象时遇到问题。对象如下：

export default [
  {
    "Type": "Buy",
    "Price": 0.00226752,
    "Amount": 55.95995977,
    "Total": 0.12689032
  },
  {
    "Type": "Buy",
    "Price": 0.00226752,
    "Amount": 146.1,
    "Total": 0.33128467
  },
  {
    "Type": "Buy",
    "Price": 0.00226684,
    "Amount": 150,
    "Total": 0.340026
  },
  {
    "Type": "Buy",
    "Price": 0.00226684,
    "Amount": 26.79415765,
    "Total": 0.06073806
  },
  {
    "Type": "Buy",
    "Price": 0.00226684,
    "Amount": 4.25269162,
    "Total": 0.00964017
  },
  {
    "Type": "Buy",
    "Price": 0.00226659,
    "Amount": 25.79415765,
    "Total": 0.05846477
  },
  {
    "Type": "Buy",
    "Price": 0.00225784,
    "Amount": 4.48789501,
    "Total": 0.01013294
  },
  {
    "Type": "Buy",
    "Price": 0.00226659,
    "Amount": 1,
    "Total": 0.00226659
  },
  {
    "Type": "Buy",
    "Price": 0.00226663,
    "Amount": 225,
    "Total": 0.50999175
  },
  {
    "Type": "Buy",
    "Price": 0.00226662,
    "Amount": 113.4736507,
    "Total": 0.25720164
  },
  {
    "Type": "Buy",
    "Price": 0.00226659,
    "Amount": 26.79415765,
    "Total": 0.06073136
  },
  {
    "Type": "Buy",
    "Price": 0.00226651,
    "Amount": 57.98798342,
    "Total": 0.13143034
  },
  {
    "Type": "Buy",
    "Price": 0.00226649,
    "Amount": 40.19123647,
    "Total": 0.09109303
  },
  {
    "Type": "Buy",
    "Price": 0.00224958,
    "Amount": 11.83690383,
    "Total": 0.02662806
  },
  {
    "Type": "Sell",
    "Price": 0.00241238,
    "Amount": 838,
    "Total": 2.02157444
  },
  {
    "Type": "Buy",
    "Price": 0.00231078,
    "Amount": 9.95795791,
    "Total": 0.02301064
  },
  {
    "Type": "Sell",
    "Price": 0.0025,
    "Amount": 4.1999832,
    "Total": 0.01049995
  },
  {
    "Type": "Sell",
    "Price": 0.0025,
    "Amount": 4.99998,
    "Total": 0.01249995
  },
  {
    "Type": "Buy",
    "Price": 0.00226702,
    "Amount": 3.63623022,
    "Total": 0.0082434
  },
  {
    "Type": "Buy",
    "Price": 0.00226702,
    "Amount": 2.14933238,
    "Total": 0.00487257
  },
  {
    "Type": "Buy",
    "Price": 0.00226702,
    "Amount": 15,
    "Total": 0.0340053
  },
  {
    "Type": "Buy",
    "Price": 0.00226702,
    "Amount": 56.80528353,
    "Total": 0.12877871
  },
  {
    "Type": "Buy",
    "Price": 0.00227634,
    "Amount": 76.88367619,
    "Total": 0.17501338
  },
  {
    "Type": "Sell",
    "Price": 0.0000141,
    "Amount": 12444,
    "Total": 0.17546011
  },
  {
    "Type": "Buy",
    "Price": 0.0000141,
    "Amount": 12131.09257,
    "Total": 0.1710484
  },
  {
    "Type": "Buy",
    "Price": 0.00001409,
    "Amount": 344.0847392,
    "Total": 0.00484815
  },
  {
    "Type": "Buy",
    "Price": 0.00249461,
    "Amount": 154.2853438,
    "Total": 0.38488176
  },
  {
    "Type": "Buy",
    "Price": 0.00249461,
    "Amount": 33.72938801,
    "Total": 0.08414166
  },
  {
    "Type": "Buy",
    "Price": 0.00246953,
    "Amount": 340.8737595,
    "Total": 0.84179797
  },
  {
    "Type": "Buy",
    "Price": 0.00246953,
    "Amount": 90.36231511,
    "Total": 0.22315244
  },
  {
    "Type": "Buy",
    "Price": 0.00246952,
    "Amount": 55.17093479,
    "Total": 0.13624572
  },
  {
    "Type": "Buy",
    "Price": 0.00246764,
    "Amount": 5.75660177,
    "Total": 0.01420522
  },
  {
    "Type": "Buy",
    "Price": 0.00245929,
    "Amount": 4.1587629,
    "Total": 0.0102276
  },
  {
    "Type": "Sell",
    "Price": 0.00252904,
    "Amount": 37.42985716,
    "Total": 0.0946616
  },
  {
    "Type": "Sell",
    "Price": 0.00252904,
    "Amount": 0.59310808,
    "Total": 0.00149999
  },
  {
    "Type": "Sell",
    "Price": 0.00252904,
    "Amount": 1.97703476,
    "Total": 0.00499999
  },
  {
    "Type": "Sell",
    "Price": 0.00252902,
    "Amount": 446.0229574,
    "Total": 1.12800097
  },
  {
    "Type": "Sell",
    "Price": 0.00252903,
    "Amount": 1.97704258,
    "Total": 0.00499999
  },
  {
    "Type": "Sell",
    "Price": 0.00259459,
    "Amount": 38.54173491,
    "Total": 0.09999999
  },
  {
    "Type": "Sell",
    "Price": 0.00259483,
    "Amount": 105.9381622,
    "Total": 0.27489152
  },
  {
    "Type": "Sell",
    "Price": 0.00259484,
    "Amount": 0.03853803,
    "Total": 0.0001
  },
  {
    "Type": "Sell",
    "Price": 0.00259484,
    "Amount": 0.03853803,
    "Total": 0.0001
  },
  {
    "Type": "Sell",
    "Price": 0.00259485,
    "Amount": 1.91102375,
    "Total": 0.00495881
  },
  {
    "Type": "Sell",
    "Price": 0.00259459,
    "Amount": 2,
    "Total": 0.00518918
  },
  {
    "Type": "Sell",
    "Price": 0.00259464,
    "Amount": 1.90549392,
    "Total": 0.00494407
  },
  {
    "Type": "Sell",
    "Price": 0.00259465,
    "Amount": 28.65568722,
    "Total": 0.07435147
  },
  {
    "Type": "Buy",
    "Price": 0.01740491,
    "Amount": 0.20683711,
    "Total": 0.00359998
  },
  {
    "Type": "Buy",
    "Price": 0.00238916,
    "Amount": 79.70696671,
    "Total": 0.19043269
  },
  {
    "Type": "Buy",
    "Price": 0.00237524,
    "Amount": 37.90636505,
    "Total": 0.09003671
  },
  {
    "Type": "Buy",
    "Price": 0.00237524,
    "Amount": 2.00494017,
    "Total": 0.00476221
  },
  {
    "Type": "Buy",
    "Price": 0.00237524,
    "Amount": 18.57724489,
    "Total": 0.04412541
  },
  {
    "Type": "Sell",
    "Price": 0.00585,
    "Amount": 56.99961222,
    "Total": 0.33344773
  },
  {
    "Type": "Sell",
    "Price": 0.00585,
    "Amount": 0.00007739,
    "Total": 4.5e-7
  },
  {
    "Type": "Sell",
    "Price": 0.00585,
    "Amount": 0.00031039,
    "Total": 0.00000181
  },
  {
    "Type": "Buy",
    "Price": 8.6e-7,
    "Amount": 2070,
    "Total": 0.0017802
  },
  {
    "Type": "Buy",
    "Price": 0.00187861,
    "Amount": 65.81153335,
    "Total": 0.1236342
  },
  {
    "Type": "Buy",
    "Price": 0.00187858,
    "Amount": 15.66747734,
    "Total": 0.0294326
  },
  {
    "Type": "Buy",
    "Price": 0.00187857,
    "Amount": 7.94470487,
    "Total": 0.01492468
  },
  {
    "Type": "Buy",
    "Price": 0.00187853,
    "Amount": 0.78814015,
    "Total": 0.00148054
  },
  {
    "Type": "Buy",
    "Price": 0.00187852,
    "Amount": 0.78814429,
    "Total": 0.00148054
  },
  {
    "Type": "Sell",
    "Price": 0.00054142,
    "Amount": 0.9975,
    "Total": 0.00054006
  },
  {
    "Type": "Buy",
    "Price": 8.6e-7,
    "Amount": 811.9167491,
    "Total": 0.00069824
  },
  {
    "Type": "Buy",
    "Price": 8.6e-7,
    "Amount": 338.0832509,
    "Total": 0.00029075
  },
  {
    "Type": "Buy",
    "Price": 0.00238719,
    "Amount": 72,
    "Total": 0.17187768
  },
  {
    "Type": "Buy",
    "Price": 0.00236363,
    "Amount": 4,
    "Total": 0.00945452
  },
  {
    "Type": "Sell",
    "Price": 0.00023501,
    "Amount": 41.1642077,
    "Total": 0.009674
  },
  {
    "Type": "Sell",
    "Price": 0.00023501,
    "Amount": 2.7697923,
    "Total": 0.00065092
  },
  {
    "Type": "Buy",
    "Price": 0.00000105,
    "Amount": 1270,
    "Total": 0.0013335
  },
  {
    "Type": "Buy",
    "Price": 0.00281001,
    "Amount": 360,
    "Total": 1.0116036
  },
  {
    "Type": "Buy",
    "Price": 0.00280001,
    "Amount": 3.33990832,
    "Total": 0.00935177
  },
  {
    "Type": "Sell",
    "Price": 0.0038,
    "Amount": 208,
    "Total": 0.7904
  },
  {
    "Type": "Sell",
    "Price": 0.00356245,
    "Amount": 1,
    "Total": 0.00356245
  },
  {
    "Type": "Sell",
    "Price": 0.00370002,
    "Amount": 0.02702689,
    "Total": 0.0001
  },
  {
    "Type": "Sell",
    "Price": 0.00370002,
    "Amount": 15.4008193,
    "Total": 0.05698333
  },
  {
    "Type": "Sell",
    "Price": 0.00370002,
    "Amount": 3.09119995,
    "Total": 0.0114375
  },
  {
    "Type": "Sell",
    "Price": 0.02315202,
    "Amount": 6.98549994,
    "Total": 0.16172843
  },
  {
    "Type": "Sell",
    "Price": 0.02315202,
    "Amount": 6e-8,
    "Total": 0
  },
  {
    "Type": "Buy",
    "Price": 0.00023492,
    "Amount": 40,
    "Total": 0.0093968
  },
  {
    "Type": "Sell",
    "Price": 0.00004456,
    "Amount": 40.3006157,
    "Total": 0.00179579
  },
  {
    "Type": "Sell",
    "Price": 0.00004461,
    "Amount": 112.0824927,
    "Total": 0.00499999
  },
  {
    "Type": "Sell",
    "Price": 0.00004462,
    "Amount": 33.61721201,
    "Total": 0.00149999
  },
  {
    "Type": "Sell",
    "Price": 0.00004463,
    "Amount": 33.60967959,
    "Total": 0.0015
  },
  {
    "Type": "Buy",
    "Price": 0.0002817,
    "Amount": 4,
    "Total": 0.0011268
  },
  {
    "Type": "Buy",
    "Price": 0.00003965,
    "Amount": 55.13060038,
    "Total": 0.00218592
  },
  {
    "Type": "Buy",
    "Price": 0.00003965,
    "Amount": 104.8693996,
    "Total": 0.00415807
  },
  {
    "Type": "Sell",
    "Price": 0.00004129,
    "Amount": 149.625,
    "Total": 0.00617801
  },
  {
    "Type": "Buy",
    "Price": 0.02215591,
    "Amount": 3,
    "Total": 0.06646773
  },
  {
    "Type": "Buy",
    "Price": 0.00004073,
    "Amount": 113.3174137,
    "Total": 0.00461541
  },
  {
    "Type": "Buy",
    "Price": 0.00004072,
    "Amount": 36.68258634,
    "Total": 0.00149371
  },
  {
    "Type": "Buy",
    "Price": 0.0000525,
    "Amount": 60,
    "Total": 0.00315
  },
  {
    "Type": "Buy",
    "Price": 0.01877317,
    "Amount": 4,
    "Total": 0.07509268
  },
  {
    "Type": "Buy",
    "Price": 0.00199501,
    "Amount": 43.10755334,
    "Total": 0.08599999
  },
  {
    "Type": "Buy",
    "Price": 0.00350201,
    "Amount": 53.48162609,
    "Total": 0.18729318
  },
  {
    "Type": "Buy",
    "Price": 0.00350201,
    "Amount": 132.1260678,
    "Total": 0.46270681
  },
  {
    "Type": "Sell",
    "Price": 0.02304826,
    "Amount": 17.03647964,
    "Total": 0.39266121
  },
  {
    "Type": "Sell",
    "Price": 0.02312381,
    "Amount": 3.52,
    "Total": 0.08139581
  },
  {
    "Type": "Sell",
    "Price": 0.02324002,
    "Amount": 3.39252036,
    "Total": 0.07884224
  },
  {
    "Type": "Buy",
    "Price": 0.02459958,
    "Amount": 7,
    "Total": 0.17219706
  },
  {
    "Type": "Buy",
    "Price": 0.01378499,
    "Amount": 9,
    "Total": 0.12406491
  },
  {
    "Type": "Buy",
    "Price": 0.00581178,
    "Amount": 1,
    "Total": 0.00581178
  },
  {
    "Type": "Buy",
    "Price": 0.01498881,
    "Amount": 7,
    "Total": 0.10492167
  },
  {
    "Type": "Sell",
    "Price": 0.00001717,
    "Amount": 176.6891735,
    "Total": 0.00303375
  },
  {
    "Type": "Sell",
    "Price": 0.00001718,
    "Amount": 87.31082654,
    "Total": 0.00149999
  },
  {
    "Type": "Buy",
    "Price": 0.00001464,
    "Amount": 182.8870467,
    "Total": 0.00267746
  },
  {
    "Type": "Buy",
    "Price": 0.00001464,
    "Amount": 32.11295335,
    "Total": 0.00047013
  },
  {
    "Type": "Buy",
    "Price": 0.00596086,
    "Amount": 26,
    "Total": 0.15498236
  },
  {
    "Type": "Buy",
    "Price": 0.000017,
    "Amount": 50,
    "Total": 0.00085
  },
  {
    "Type": "Buy",
    "Price": 0.0005388,
    "Amount": 1,
    "Total": 0.0005388
  },
  {
    "Type": "Buy",
    "Price": 0.00935588,
    "Amount": 0.00060288,
    "Total": 0.00000564
  },
  {
    "Type": "Buy",
    "Price": 0.00935588,
    "Amount": 0.99939712,
    "Total": 0.00935023
  },
  {
    "Type": "Buy",
    "Price": 0.01475001,
    "Amount": 1,
    "Total": 0.01475001
  },
  {
    "Type": "Buy",
    "Price": 0.00555,
    "Amount": 21.28693846,
    "Total": 0.1181425
  },
  {
    "Type": "Buy",
    "Price": 0.00553,
    "Amount": 9.26025155,
    "Total": 0.05120919
  }
]

我看到了如何打印值：

_renderData(){
     const data = this.state.sdc
     return Object.keys(data).map(function(key,index){
         const datum = data[key]
         return ( <div key={datum.id}>
          <p>Type: {datum.Type}</p>
          <p>Price: {datum.Price}</p>
          <p>Amount: {datum.Amount}</p>
          <p>Total: {datum.Total}</p>
        </div> )
     })
  }

现在我正在尝试使用它，例如：

_extractData() {
    const data = this.state.sdc
    return Object.keys(data[0])

  }

将打印四个标题（类型，价格，金额，总计），但我真的想做一些更复杂的事情。例如

显示所有类型的交易：购买
显示总值大于x等的所有交易

我如何访问所有这些。你能提供一个例子吗？

编辑：我添加了下面建议的一种方法 - 但是它没有显示任何内容：

import React, {Component} from 'react';
import Header from './header/header';
import Body from './body/body';
import sdc from './data';

export default class App extends Component {
  constructor(props) {
    super();
    // Set the initial grid in
    this.state = {
      title: "Singularity is nigh!!!",
      sdc: sdc
    };

  }

  _renderData(){
     const data = this.state.sdc
     return Object.keys(data).map(function(key,index){
         const datum = data[key]
         return ( <div key={datum.id}>
          <p>Type: {datum.Type}</p>
          <p>Price: {datum.Price}</p>
          <p>Amount: {datum.Amount}</p>
          <p>Total: {datum.Total}</p>
        </div> )
     })
  }


  _extractData() {
    const data = this.state.sdc
    return Object.keys(data[0])

  }

  _renderBuy() {
    const data = this.state.sdc
    data.filter(function(element) {
      return element.hasOwnProperty("Type") && element.Type == 'Buy';
  });

  }

  render() {
    const renderedData = this._renderBuy()


    return (
      // Add your component markup and other subcomponent references here.
      <div>
        <Header title={this.state.title} />
        {renderedData}    
      </div>

    );
  }
}

Answer 1

我认为这更像是一般的javascript问题。您要求的是过滤数组中的对象列表，因此通过使用数组的filter方法来实现这一目的。

// Filter all the transactions of type 'Buy'
data.filter(function(element) { 
  return element.hasOwnProperty("Type") && element.Type == 'Buy'; 
});

// Filter all the transactions having a total amount greater than or equal to 0.84
data.filter(function(element) { 
  return element.hasOwnProperty("Total") && element.Total >= 0.84; 
});

从filter获得的输出只是一个新的对象数组，其中的元素通过了测试，所以为了在React中呈现它们，你需要遍历这个新返回的数组，就像你一样在你的_renderData()实例方法中做了。

我对你的_renderData方法进行了一些细微的修改，以便它接受一个参数，该参数可以是任何对象数组，因此您不必再次重复相同的代码来呈现“购买”事务或任何其他过滤的数组。

_renderData(data){
   return Object.keys(data).map(function(key,index){
       const datum = data[key]
       return ( <div key={datum.id}>
        <p>Type: {datum.Type}</p>
        <p>Price: {datum.Price}</p>
        <p>Amount: {datum.Amount}</p>
        <p>Total: {datum.Total}</p>
      </div> )
   })
}

render() {
  const renderedData = this._renderData(this._renderBuy());

  return (
    // Add your component markup and other subcomponent references here.
    <div>
      <Header title={this.state.title} />
      {renderedData}    
    </div>

  );
};

jsBin

JS - 它是什么类型的对象以及如何访问它

1 个答案: