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如何定位數(shù)組中的對象子集并將屬性更改為每個對象的遞增數(shù)字？

如何定位數(shù)組中的對象子集并將屬性更改為每個對象的遞增數(shù)字？

LEATH 2022-10-08 10:23:12
我正在努力對一組對象進行相當復雜的操作。首先這是一個示例數(shù)組：[  {id: 11, item: 132, lineNum: 4, linePosition: 5}  {id: 2, item: 124, lineNum: 0, linePosition: 2}  {id: 9, item: 130, lineNum: 0, linePosition: 5}  {id: 12, item: 133, lineNum: 1, linePosition: 3}  {id: 15, item: 136, lineNum: 3, linePosition: 2}  {id: 13, item: 134, lineNum: 0, linePosition: 4}  {id: 10, item: 131, lineNum: 2, linePosition: 1}  {id: 8, item: 129, lineNum: 3, linePosition: 3}  {id: 1, item: 123, lineNum: 0, linePosition: 5}  {id: 3, item: 125, lineNum: 1, linePosition: 7}  {id: 5, item: 127, lineNum: 0, linePosition: 9}  {id: 7, item: 128, lineNum: 1, linePosition: 2}  {id: 4, item: 126, lineNum: 0, linePosition: 4}  {id: 14, item: 135, lineNum: 3, linePosition: 9}]所以我想盡可能高效地按順序進行以下操作。按 lineNum 對數(shù)組進行排序，然后按項目升序排序。然后我想修改每個對象，lineNum === 0使 linePosition 從 0 開始遞增。所以第一個匹配對象的 linePosition 為 0，下一個是 1，然后是 2，等等。結(jié)果數(shù)組如下所示：[  {id: 1, item: 123, lineNum: 0, linePosition: 0}  {id: 2, item: 124, lineNum: 0, linePosition: 1}  {id: 4, item: 126, lineNum: 0, linePosition: 2}  {id: 5, item: 127, lineNum: 0, linePosition: 3}  {id: 9, item: 130, lineNum: 0, linePosition: 4}  {id: 13, item: 134, lineNum: 0, linePosition: 5}  {id: 3, item: 125, lineNum: 1, linePosition: 7}  {id: 7, item: 128, lineNum: 1, linePosition: 2}  {id: 12, item: 133, lineNum: 1, linePosition: 3}  {id: 10, item: 131, lineNum: 2, linePosition: 1}  {id: 8, item: 129, lineNum: 3, linePosition: 3}  {id: 14, item: 135, lineNum: 3, linePosition: 9}  {id: 15, item: 136, lineNum: 3, linePosition: 2}  {id: 11, item: 132, lineNum: 4, linePosition: 5}]
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瀟湘沐

TA貢獻1816條經(jīng)驗 獲得超6個贊

Array.prototype.sort()

let arr = getData();


arr.sort(function(a, b) {

  if( a.lineNum === b.lineNum ) {

    return a.item - b.item;

  } else {

    return a.lineNum - b.lineNum;

  }

});

// return a.lineNum === b.lineNum ? a.item - b.item : a.lineNum - b.lineNum;


for( let i = 0; i < arr.length; i++ ) {

  if( arr[i].lineNum > 0 ) break;

  arr[i].linePosition = i;

}

// Used classic loop, to break it and avoid unnecessary iterations.


console.log( JSON.stringify(arr).replace(/\},/g, "},\n") );


/***/

function getData() {

  return [

    {id: 11, item: 132, lineNum: 4, linePosition: 5},

    {id: 2, item: 124, lineNum: 0, linePosition: 2},

    {id: 9, item: 130, lineNum: 0, linePosition: 5},

    {id: 12, item: 133, lineNum: 1, linePosition: 3},

    {id: 15, item: 136, lineNum: 3, linePosition: 2},

    {id: 13, item: 134, lineNum: 0, linePosition: 4},

    {id: 10, item: 131, lineNum: 2, linePosition: 1},

    {id: 8, item: 129, lineNum: 3, linePosition: 3},

    {id: 1, item: 123, lineNum: 0, linePosition: 5},

    {id: 3, item: 125, lineNum: 1, linePosition: 7},

    {id: 5, item: 127, lineNum: 0, linePosition: 9},

    {id: 7, item: 128, lineNum: 1, linePosition: 2},

    {id: 4, item: 126, lineNum: 0, linePosition: 4},

    {id: 14, item: 135, lineNum: 3, linePosition: 9},

  ];

}

.as-console-wrapper { max-height: 100vh !important; }


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ABOUTYOU

TA貢獻1812條經(jīng)驗 獲得超5個贊

您可以使用 Javascript.sort()函數(shù)完成上述任務(wù)。它可以采用可選的比較函數(shù)參數(shù)，該參數(shù)指定定義排序順序的函數(shù)。


let arr = [

  {id: 11, item: 132, lineNum: 4, linePosition: 5},

  {id: 2, item: 124, lineNum: 0, linePosition: 2},

  {id: 9, item: 130, lineNum: 0, linePosition: 5},

  {id: 12, item: 133, lineNum: 1, linePosition: 3},

  {id: 15, item: 136, lineNum: 3, linePosition: 2},

  {id: 13, item: 134, lineNum: 0, linePosition: 4},

  {id: 10, item: 131, lineNum: 2, linePosition: 1},

  {id: 8, item: 129, lineNum: 3, linePosition: 3},

  {id: 1, item: 123, lineNum: 0, linePosition: 5},

  {id: 3, item: 125, lineNum: 1, linePosition: 7},

  {id: 5, item: 127, lineNum: 0, linePosition: 9},

  {id: 7, item: 128, lineNum: 1, linePosition: 2},

  {id: 4, item: 126, lineNum: 0, linePosition: 4},

  {id: 14, item: 135, lineNum: 3, linePosition: 9}

];


//sorting the given array, first based on lineNum, then by item

arr.sort(function(a,b){

  if(a.lineNum !== b.lineNum)

    return a.lineNum - b.lineNum;

  return a.item - b.item;

});


// modify each object where lineNum===0, linePosition starting from 0

// since we have sorted, break when first lineNum > 0

let linePos = 0;

for( let i = 0; i < arr.length; i++ ) {

  if( arr[i].lineNum > 0 ) 

    break;

  if(arr[i].lineNum === 0)

    arr[i].linePosition = linePos++;

}


//   console.log(arr); //<-- This prints as array


console.log( JSON.stringify(arr).replace(/\},/g, "},\n") ); // <-- This prints your mentioned format


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