I want to extract a subarray of Columns from a multidimensional array and mutate the original array to remove those columns in JavaScript

Ex: If I have an array

originalArray =
[
 [A, B, C, D, E, F],
 [a1,b1,c1,d1,e1,f1],
 [a2,b2,c2,d2,e2,f2],
 [a3,b3,c3,d3,e3,f3]
[  

Where A,B,C,D,E,F are headers and I want to extract columns [4,0,3] in this order I would get

subArray =
[
 [E, A, D],
 [e1,a1,d1],
 [e2,a2,d2],
 [e3,a3,d3]
[


originalArray = 
[
 [B, C, F],
 [b1,c1,f1],
 [b2,c2,f2],
 [b3,c3,f3]
[  

I found this: Extract subarray from a multidimensional array and mutate the original array

which does this for rows

let subArray = originalArray.reduce((accumulator, current, index) => {
    if (idxList.includes(index)) {
      //if the current index is included in the idxList array, 
      //push the current value to the accumulator
      accumulator.push(current);
    } else {
      //push the current value to the `tempArray`.
      tempArray.push(current)
    }
    return accumulator;
  }, []);

Then I will concatenate these two arrays

reorderedArray = [...subArray, ...originalArray]

Reduce seems like an interesting approach and it seems like it should be a simple fix but I have to admit I am having a hard time understanding Reduce

Thanks in advance for your assistance

CodePudding user response：

You could add the missing indices to order and map the array by mapping nested array with the indices of order.

let
    data = [['A', 'B', 'C', 'D', 'E', 'F'], ['a1', 'b1', 'c1', 'd1', 'e1', 'f1'], ['a2', 'b2', 'c2', 'd2', 'e2', 'f2'], ['a3', 'b3', 'c3', 'd3', 'e3', 'f3']],
    order = [4, 0, 3],
    seen = new Set(order),
    i = 0;

while (order.length < data[0].length) {
    while (seen.has(i))   i;
    order.push(i  );
}

data = data.map(a => order.map(i => a[i]));

data.forEach(a => console.log(...a));

<iframe name="sif1" sandbox="allow-forms allow-modals allow-scripts" frameborder="0"></iframe>

CodePudding user response：

regular mapping seems like it would work:

function myFunction() {
  var originalArray = SpreadsheetApp.getActive().getRange('Sheet1!A:F').getValues();
  var subarray = originalArray.map(e=>[e[4],e[0],e[3]]);
  originalArray = originalArray.map(e=>[e[1],e[2],e[5]]);

}