Question

我正在尝试按项属性对项目数组进行分组，然后从0开始重新索引结果。

以下函数返回一组分组的项目。

groupItemBy(array, property) {
  let hash = {},
  props = property.split('.');
    for (let i = 0; i < array.length; i++) {
      let key = props.reduce( (acc, prop) => {
        return acc && acc[prop];
      }, array[i]);
      if (!hash[key]) hash[key] = [];
        hash[key].push(array[i]);
      }
      return hash;
}

结果是一个数组数组，类似于：

[{
  "1193312":[
    {
      "description":"Item 1",
      "number": "1193312"
    }
  ],
  "1193314":[
    {
      "itemDesc":"Item 2"},
      "number": "1193314"
    {
      "description":"Item 3",
      "number": "1193314"
    }
  ],
  etc...
}]

从这里开始，我想将1193312映射到0，将1193314映射到1等。

我在结果上尝试.filter(val => val)，但这似乎没有效果。

Answer 1

您需要使用中间密钥替换：

function groupItemBy(array, property) {
  let hash = {}
  let props = property.split('.')
  let keys = []

  for (let i = 0; i < array.length; i++) {
    let key = props.reduce((acc, prop) => {
      return acc && acc[prop];
    }, array[i]);
    let subst = keys.indexOf(key)
    if (subst === -1) {
        keys.push(key)
        subst = keys.length - 1
    }
    if (!hash[subst]) hash[subst] = [];
    hash[subst].push(array[i]);
  }
  return hash;
}

[https://jsfiddle.net/05t9141p/]

Answer 2

您可以将map用于数组部分，将Object.values和reduce用于重新编号部分。

const data = [{
  "1193312":[
    {
      "time":"2018-02-20",
      "description":"Item 1",
      "number": "1193312"
    }
  ],
  "1193314":[
    {
      "time":"2018-02-21",
      "itemDesc":"Item 2",
      "number": "1193314"
    },{
      "time":"2018-02-21",
      "description":"Item 3",
      "number": "1193314"
    }
  ]
}];

const renumbered =
  data.map((m) => Object.values(m).reduce((a,v,ix) => (a[ix] = v, a), {}));
  
console.log(renumbered);

Answer 3

const options: CameraOptions = {
  quality: 50,
  destinationType: this.camera.DestinationType.DATA_URL,
  encodingType: this.camera.EncodingType.PNG,
  mediaType: this.camera.MediaType.PICTURE,
  sourceType: isCamera ? this.camera.PictureSourceType.CAMERA : this.camera.PictureSourceType.PHOTOLIBRARY,
  correctOrientation: true,
}

Answer 4

如果您可以使用var output = { suba: inputArray[n].integervalue, subb: inputArray[n].integervalue; subc: inputArray[n].integervalue; subd: inputArray[n].booleanvalue; sube: inputArray[n].booleanvalue; sudf: inputArray[n].booleanvalue; }：

＆＃13;

#include <stdio.h>
int main(void)
{
int state;

for(state=0; ; ) {
        int ch;
        ch = getc(stdin);
        if (ch == EOF) break;
        switch (state) {
        case 0: /* initial */
                if (ch == '.') { state = 1; continue; }
                break;
        case 1:
                if (ch == '\n') { state = 0; break; }
                continue;
                }
        putc(ch, stdout);
        }
return 0;
}

＆＃13;

如何按属性和重新索引结果对数组进行分组

4 个答案: