在应用程序脚本中从2D数组提取选定列的最佳方法 [英] Best method to extract selected columns from 2d array in apps script

问题描述

我正在使用Google Apps脚本.如果我从范围A1:E5之类的范围开始，那就是一个5x5的数组.我想返回范围C1:D5，一个5x2数组.从二维数组开始，仅返回选定的列".基本上就是这样.我认为这是一项基本操作，但我确实很挣扎.我在下面有我的代码，但是我可以使用任何使用数组的选项(而不是范围，以便避免不必要地对服务器执行ping操作).请注意，我确实希望能够为列传递数组参数，所以[2,3,4]或[2]或[3,4]不仅是单个值或静态值.感谢您的帮助.

I'm working in google apps script. If I start with a range like range A1:E5, that's a 5x5 array. I want to return range C1:D5, a 5x2 array. Start with a 2d array and return only selected 'columns'. That's basically it. I think it's a fundamental operation, but I'm really struggling. I have my code below, but I'm open to any options that use arrays (not ranges, so as to avoid pinging the server unnecessarily). Note that I do want to be able to pass an array parameter for columns, so [2,3,4] or [2] or [3,4], not just a single or static value. Thanks for any help.

/**
 * extracts selected 'columns' (2nd dimension) from 2d array
 *
 * @arr {array} larger 2d array to be subset
 * @cols {array} subset of columns, eg, [3,4]
 * @return 2d array with only selected cols
 * @customfunction
 */
function getCols(arr,cols) {
  var ss = SpreadsheetApp.getActiveSpreadsheet();  

  var arrRows = [];
  var arrCols = [];
  
  for(var r=0;r<arr.length;r++){
    arrCols = [];// reset snippet
  for(var c=0;c<cols.length;c++){
    arrCols.push([arr[r][cols[c]]]); // iterate to make 1xc array snippet
  }
    arrRows[r].push(arrCols); // iterate to add each row
  }
  
  return arrRows; // return new arr subset that only has requested cols
}

推荐答案

使用 Array#filter 与地图:

/**
 * extracts selected 'columns' (2nd dimension) from 2d array
 *
 * @param {Object[][]} arr larger 2d array to be subset
 * @param {Number[]} cols Indexes of subset of columns needed starting from 1 eg, [3,4]
 * @return {Object[][]} 2d array with only selected cols
 * @customfunction
 */
function getCols(arr,cols) {
  return arr.map(row =>
    row.filter((_,i) => cols.includes(++i)))
}
console.info(getCols([[1,2,3],[4,5,6]],[1,3]));
console.info(getCols([[1,2,3],[4,5,6]],[2,3]));

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