javascript - 我需要获取数组中值的中位数，但我卡住了

Question

我正在尝试做这样的事情，但我尝试了多少次都无法正确。我已经尝试了很多方法，目前我已经让它显示项目的总和，但它会跳过每个嵌套数组开头的名称。

           00-08 08-16 16-24 medel
Malmö      12    16    9     12.3
Mariestad  13    15    10    12.7
Stockholm  13    15    13    13.7
Upphärad   14    16    15    15
Göteborg   13    14    12    13 


var tempen = [
  ["", "00-08", "08-16", "16-24"],
  ["Malmö", 12, 16, 9],
  ["Mariestad", 13, 15, 10],
  ["Stockholm", 13, 15, 13],
  ["Upphärad", 14, 16, 15],
  ["Göteborg", 13, 14, 12]
];
var newArray = tempen.slice();
tempen[0].push("medel");

function sum_value(prev_value, next_value, ) {
  return ( prev_value + next_value);
};

for (var i = 1; i < newArray.length; i++) {
  newArray[i].shift();
  var sum = newArray[i].reduce(sum_value);
  newArray[i].push(sum);
}

function printit() {
  var varMyinnerHTML = "<table>";
  for (var i = 0; i < tempen.length; i++) {
    varMyinnerHTML += "<tr>";
    for (var j = 0; j < tempen[i].length; j++) {
      varMyinnerHTML += "<td>" + tempen[i][j] + "</td>";
    }
    varMyinnerHTML += "</tr>";
  }
  document.getElementById("kontainer").innerHTML = varMyinnerHTML;
}

任何帮助都会很棒，我真的很不擅长:(

Answer 1

你就快到了!这是您的代码，只需进行最少的修改即可正常工作。评论中描述了这些修复。

主要修复:

• but it skips the name in the beginning of every nested array

  计算总和时，必须删除地名 string确保你不会得到 NaN 。但是，您通过使用 shift 来做到这一点，这将其从您仍需要渲染表格的原始数组中删除。要创建仅包含数字的新数组，可以使用 slice 。这不会改变原始数组，因此您以后仍然可以访问地名。

• i have got it to show the sum of the items

  您只是按 sum ，但忘记除以值的数量!

• 您忘记关闭<table>标签

var tempen = [
  ["", "00-08", "08-16", "16-24"],
  ["Malmö", 12, 16, 9],
  ["Mariestad", 13, 15, 10],
  ["Stockholm", 13, 15, 13],
  ["Upphärad", 14, 16, 15],
  ["Göteborg", 13, 14, 12]
];

// We don't need a new array
tempen[0].push("medel");

function sum_value(prev_value, next_value) {
  return (prev_value + next_value);
};


for (var i = 1; i < tempen.length; i++) {

  // Don't delete the place names from the orginal!
  // newArray[i].shift();
  
  // Only skip the place name for the sum
  var numbers = tempen[i].slice(1);
  
  var sum = numbers.reduce(sum_value);
  
  // Here, we compute the average by dividing
  // sum by length:
  var avg = sum / numbers.length;

  // Push the average, not the sum:
  tempen[i].push(avg);
}


function printit() {
  // Add a body
  var varMyinnerHTML = "<table><tbody>";
  
  for (var i = 0; i < tempen.length; i++) {

    varMyinnerHTML += "<tr>";
    for (var j = 0; j < tempen[i].length; j++) {
      varMyinnerHTML += "<td>" + tempen[i][j] + "</td>";
    }
    varMyinnerHTML += "</tr>";
  }
  
  // Close the body and table
  varMyinnerHTML += "</tbody></table>"

  document.getElementById("kontainer").innerHTML = varMyinnerHTML;
}

// Run the code
printit();

<div id="kontainer"></div>