将二维数组的每一列相乘并返回数组

Question

这里是JS的新手。如何使用math.js或vanilla js返回一个二维数组乘以每列的数组？两个数组的大小将始终相同。

[[2,2],
[2,4]]

结果是

[4,8]

我试过了：

adjustedrating = [[2,2],[2,4]]
var w = adjustedrating.length;

for (var i = 0, len = adjustedrating[0].length; i < len; i++) {
  var multiple = adjustedrating[0][i];
  for (var j = 0; j < w; j++) {
      multiple *= adjustedrating[j][i];

  }
  both.push(multiple);
};

Answer 1

你能做的就是遍历外部数组，并存储乘法的结果。例如：

​

// The two dimensional array
var twoDimArray = [[2,2],
                   [2,4]];

// We'll say this is where your results will go. It will be the same length
//     as one of your inner arrays, and all values will start at 1
var results = [1,1];

// Loop through the 2D Array
for( var outerIndex = 0; outerIndex < twoDimArray.length; outerIndex++){
    // Loop through the currently selected inner array
    for( var innerIndex = 0; innerIndex < twoDimArray[outerIndex].length; innerIndex++){
        // Multiply appropriate result by the appropriate value
        results[innerIndex] *= twoDimArray[outerIndex][innerIndex];
    }
}

// Simply displays the results somewhere
document.getElementById('results').innerHTML = results;

<div id="results"></div>

​