Learn Advanced Array Methods by Building a Statistics Calculator - Step 35

JavaScript
1

Tell us what’s happening:

I am confused as to why this is not accepting this. The getMode function is working as it should by this step according to console log. If i put in the number set 4, 4, 2, 5 it returns { 2:1. 4:2, 5:1 } in the console. Yet it keeps saying I’m not using a ternary operator, however it should not be functioning without said ternary operator.

Your code so far

<!-- file: index.html -->
<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="utf-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1" />
    <link rel="stylesheet" href="./styles.css" />
    <script src="./script.js"></script>
    <title>Statistics Calculator</title>
  </head>
  <body>
    <h1>Statistics Calculator</h1>
    <p>Enter a list of comma-separated numbers.</p>
    <form onsubmit="calculate(); return false;">
      <label for="numbers">Numbers:</label>
      <input type="text" name="numbers" id="numbers" />
      <button type="submit">Calculate</button>
    </form>
    <div class="results">
      <p>
        The <dfn>mean</dfn> of a list of numbers is the average, calculated by
        taking the sum of all numbers and dividing that by the count of numbers.
      </p>
      <p class="bold">Mean: <span id="mean"></span></p>
      <p>
        The <dfn>median</dfn> of a list of numbers is the number that appears in
        the middle of the list, when sorted from least to greatest.
      </p>
      <p class="bold">Median: <span id="median"></span></p>
      <p>
        The <dfn>mode</dfn> of a list of numbers is the number that appears most
        often in the list.
      </p>
      <p class="bold">Mode: <span id="mode"></span></p>
      <p>
        The <dfn>range</dfn> of a list of numbers is the difference between the
        largest and smallest numbers in the list.
      </p>
      <p class="bold">Range: <span id="range"></span></p>
      <p>
        The <dfn>variance</dfn> of a list of numbers measures how far the values
        are from the mean, on average.
      </p>
      <p class="bold">Variance: <span id="variance"></span></p>
      <p>
        The <dfn>standard deviation</dfn> of a list of numbers is the square
        root of the variance.
      </p>
      <p class="bold">
        Standard Deviation: <span id="standardDeviation"></span>
      </p>
    </div>
  </body>
</html>

/* file: styles.css */
body {
  margin: 0;
  background-color: rgb(27, 27, 50);
  text-align: center;
  color: #fff;
}

button {
  cursor: pointer;
  background-color: rgb(59, 59, 79);
  border: 3px solid white;
  color: white;
}

input {
  background-color: rgb(10, 10, 35);
  color: white;
  border: 1px solid rgb(59, 59, 79);
}

.bold {
  font-weight: bold;
}

/* file: script.js */
const getMean = (array) => array.reduce((acc, el) => acc + el, 0) / array.length;

const getMedian = (array) => {
  const sorted = array.sort((a, b) => a - b);
  const median =
    array.length % 2 === 0
      ? getMean([sorted[array.length / 2], sorted[array.length / 2 - 1]])
      : sorted[Math.floor(array.length / 2)];
  return median;
}


// User Editable Region

const getMode = (array) => {
  const counts = {};
  array.forEach(el => counts[el] = counts[el] ? counts[el] += 1 : counts[el] = 1);
  return counts;
  }

// User Editable Region


const calculate = () => {
  const value = document.querySelector("#numbers").value;
  const array = value.split(/,\s*/g);
  const numbers = array.map(el => Number(el)).filter(el => !isNaN(el));
  
  const mean = getMean(numbers);
  const median = getMedian(numbers);
  console.log(getMode(numbers));

  document.querySelector("#mean").textContent = mean;
  document.querySelector("#median").textContent = median;
}

Your browser information:

User Agent is: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:133.0) Gecko/20100101 Firefox/133.0

Challenge Information:

Learn Advanced Array Methods by Building a Statistics Calculator - Step 35

2

you have too many assignment operators in this statement.
The only one that should be there is the first one. That is:
Everything you wrote up to this point below is correct
array.forEach(el => counts[el] = counts[el] ?

Rewrite the remainder of the line of code so that the first ‘truthy’ statement just assigns the value plus 1, while the falsey should assign 1.
(I hope that’s enough of a clue for you)

2 Likes
3

It was! Thank you so much for the help

1 Like