JavaScript - Sorting Arrays

Sort()

<p id="demo1"></p>
<p id="demo2"></p>

<script>
const fruits = ["Banana", "Orange", "Apple", "Mango"];
document.getElementById("demo1").innerHTML = fruits;

fruits.sort();
document.getElementById("demo2").innerHTML = fruits;
</script>

Banana,Orange,Apple,Mango
Apple,Banana,Mango,Orange

 

 

reverse()

<p id="demo1"></p>
<p id="demo2"></p>

<script>
// Create and display an array:
const fruits = ["Banana", "Orange", "Apple", "Mango"];
document.getElementById("demo1").innerHTML = fruits;

// First sort the array
fruits.sort();

// Then reverse it:
fruits.reverse();

document.getElementById("demo2").innerHTML = fruits;
</script>

Banana,Orange,Apple,Mango
Orange,Mango,Banana,Apple

 

 

<p id="demo1"></p>
<p id="demo2"></p>

<script>
const points = [40, 100, 1, 5, 25, 10];
document.getElementById("demo1").innerHTML = points;  

points.sort(function(a, b){return a - b});
document.getElementById("demo2").innerHTML = points;
</script>

40,100,1,5,25,10
1,5,10,25,40,100

 

const points = [40, 100, 1, 5, 25, 10];
points.sort(function(a, b){return b - a});

40,100,1,5,25,10
100,40,25,10,5,1

 

 

비교 기능

function(a, b){return a - b}

함수가 두 값을 비교할 때 sort()값을 비교 함수로 보내고 반환된 값(음수, 0, 양수)에 따라 값을 정렬합니다.

결과가 음수이면 a가 앞에 정렬 b됩니다.

결과가 양수이면 b가 앞에 정렬 a됩니다.

결과가 0이면 두 값의 정렬 순서가 변경되지 않습니다.

 

 

 

무작위 순서로 배열 정렬

<p id="demo"></p>

<script>
const points = [40, 100, 1, 5, 25, 10];
document.getElementById("demo").innerHTML = points;  

function myFunction() {
  points.sort(function(){return 0.5 - Math.random()});
  document.getElementById("demo").innerHTML = points;
}
</script>

1,100,10,40,5,25

 

 

 

Fisher Yates shuffle

<p id="demo"></p>

<script>
const points = [40, 100, 1, 5, 25, 10];
document.getElementById("demo").innerHTML = points;  

function myFunction() {
  for (let i = points.length -1; i > 0; i--) {
    let j = Math.floor(Math.random() * (i+1));
    let k = points[i];
    points[i] = points[j];
    points[j] = k;
  }
  document.getElementById("demo").innerHTML = points;
}
</script>

 

 

 

Math.max()

<p>The highest number is <span id="demo"></span>.</p>

<script>
const points = [40, 100, 1, 5, 25, 10];
document.getElementById("demo").innerHTML = myArrayMax(points);

function myArrayMax(arr) {
  return Math.max.apply(null, arr);
}
</script>

The highest number is 100

 

 

 

Math.min()

<p>The lowest number is <span id="demo"></span>.</p>

<script>
const points = [40, 100, 1, 5, 25, 10];
document.getElementById("demo").innerHTML = myArrayMin(points);

function myArrayMin(arr) {
  return Math.min.apply(null, arr);
}
</script>

The lowest number is 1

 

 

Find Max

function myArrayMax(arr) {
  let len = arr.length;
  let max = -Infinity;
  while (len--) {
    if (arr[len] > max) {
      max = arr[len];
    }
  }
  return max;
}

Find Min

function myArrayMin(arr) {
  let len = arr.length;
  let min = Infinity;
  while (len--) {
    if (arr[len] < min) {
      min = arr[len];
    }
  }
  return min;
}