When precision is required, rounding numbers to two decimals

Question

When precision is required, rounding numbers to two decimals

I'm currently working on a code snippet that extracts data from an array and calculates the average. The problem I'm facing is that even if the calculated average is a whole number like 3, it still displays as 3.00. Ideally, I would like the average to only show up to 2 decimal places when necessary. Here's the code snippet:

var calculated = playerdata.map((player) => {
  const rounds = player.slice(2);

  return {
    player,
    average: average(rounds).toFixed(2),
    best: Math.min(...rounds),
    worst: Math.max(...rounds)
  };
}); 

function average(numbers) {
  return numbers.reduce((a, b) => a + b, 0) / numbers.length;
}

javascript arrays tofixed

Answer 1

Answer №1

If you wish to add a + before average(rounds).toFixed(2), you can do so like this:

+average(rounds).toFixed(2)

Here are some examples of how it works:

var roundTo2 = function(num) {
  return +num.toFixed(2);
}

console.log(roundTo2(3))
console.log(roundTo2(3.1))
console.log(roundTo2(3.12))
console.log(roundTo2(3.128))

UPDATE

Adding relevant test cases for further clarification.

Answer 2

If you wish to add a + before average(rounds).toFixed(2), you can do so like this:

+average(rounds).toFixed(2)

Here are some examples of how it works:

var roundTo2 = function(num) {
  return +num.toFixed(2);
}

console.log(roundTo2(3))
console.log(roundTo2(3.1))
console.log(roundTo2(3.12))
console.log(roundTo2(3.128))

UPDATE

Adding relevant test cases for further clarification.

Answer 3

Answer №2

@Maaz's method is effective, but here's a solution that offers more clarity:

if the number of decimal places exceeds 2, round it:
average(rounds) * 100 % 1 ? average(rounds).toFixed(2) : average(rounds)

This code snippet will only round off if the number goes beyond 2 decimal places:

f = function(a){return a * 100 % 1 ? a.toFixed(2) : a}

console.log(f(3))
console.log(f(3.1))
console.log(f(3.12))
console.log(f(3.128))

Answer 4

@Maaz's method is effective, but here's a solution that offers more clarity:

if the number of decimal places exceeds 2, round it:
average(rounds) * 100 % 1 ? average(rounds).toFixed(2) : average(rounds)

This code snippet will only round off if the number goes beyond 2 decimal places:

f = function(a){return a * 100 % 1 ? a.toFixed(2) : a}

console.log(f(3))
console.log(f(3.1))
console.log(f(3.12))
console.log(f(3.128))

Answer 5

Answer №3

You can check if a number has a decimal by comparing its rounded integer value to itself using the Math.round() function.

function checkDecimal(num){ 
  var hasDecimal = Math.round(num) !== num; 
  return hasDecimal ? num.toFixed(2) : num;  
}

console.log(checkDecimal(3.01));
console.log(checkDecimal(3.1));
console.log(checkDecimal(3));

Answer 6

You can check if a number has a decimal by comparing its rounded integer value to itself using the Math.round() function.

function checkDecimal(num){ 
  var hasDecimal = Math.round(num) !== num; 
  return hasDecimal ? num.toFixed(2) : num;  
}

console.log(checkDecimal(3.01));
console.log(checkDecimal(3.1));
console.log(checkDecimal(3));

When precision is required, rounding numbers to two decimals

Answer №1

Answer №2

Answer №3

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