// Accumulation of array
let arr = [14, 36, 43, 64, 88, 97];
function sum(arr){
const sum = arr.reduce((acc, cur) => {
return acc + cur
},0)
return sum
}
console.log(sum(arr)) // 342
// ๋ฐฐ์ด์ ์ง์๋ฒ์งธ ์ธ๋ฑ์ค๋ 2๋ก ํ์๋ฒ์งธ๋ 3
function array(n){
let arr = Array.from({length: n}, () => 2);
arr.forEach((num, i)=>{
if (i%2 !== 0){
console.log(i)
arr[i] = 3
}
})
return arr;
}
console.log(array(10)); //[ 2, 3, 2, 3, 2, 3, 2, 3, 2, 3 ]
// =============== ๋ฐฐ์ด ์ฌํ ๋น ===============
console.log(Array.from('foo'));
// expected output: Array ["f", "o", "o"]
console.log(Array.from([1, 2, 3], el => el + el));
// expected output: Array [2, 4, 6]
// =============== ๋ฐฐ์ด ์ด๊ธฐํ ===============
const arr = Array.from({length: 5}, () => 0);
console.log(arr); // => Array(5) [0, 0, 0, 0, 0]
console.log(arr[0]); // => 0
console.log(arr.length); // => 5
// ================== ์๋ฆฟ์ ๋ํ๊ธฐ ==================
function solution(n){
const answer = n.toString().split("").reduce((acc, cur) => { // toString() mdn ์ฐพ์๋ณด๊ธฐ
return acc + Number(cur)
},0) //์ด๊ธฐ๊ฐ์ผ๋ก 0์ ์ค์ ํด์ฃผ์ง ์์ผ๋ฉด acc๋ฅผ ๋ฐ์์ค๋ ๊ฐ์ด ๋ฌธ์์ด์ด ๋๋ฒ๋ฆผ ๊ทธ๋์ 0์ด๋ผ๊ณ ํ์
์ถ๋ก ์ ์์ผ์ผํจ
return answer
}
solution(123)
solution(987)
// ============ x๋งํผ ๊ฐ๊ฒฉ์ด ์๋ n๊ฐ์ ์ซ์ ============
function solution (x,n){
const answer = new Array(n)
.fill(1)
.map((el, i) => {
return (el + i) * x
})
return answer
}
solution(2,5) // [ 2, 4, 6, 8, 10 ]
"b" > "a" // true
// 98 > 97
"A" > "a" // false
// 65 > 97
์๋ฌธ์ 97 - 122
๋๋ฌธ์ 65 - 90
arr = ["a","z","b","c"]
arr.sort((a,b)=> {
console.log(a,b,a>b)
return a>b ? 1 : -1 // ์ค๋ฆ์ฐจ์
return a > b ? -1 : 1 // ๋ด๋ฆผ์ฐจ์
})
// ============ ๋ฌธ์์ด ๋ด๋ฆผ์ฐจ์์ผ๋ก ๋ฐฐ์นํ๊ธฐ ============
function solution(s){
// const answer = s.split("") === Array.from(s)
// ๋ฌธ์์ด์ ๋ฐฐ์ด๋ก ๋ง๋ค๊ธฐ
const answer = Array.from(s)
answer.sort((a,b) => {
return a > b ? -1 : 1 //๋ด๋ฆผ์ฐจ์
})
// ๋ค์ ๋ฐฐ์ด์ ๋ฌธ์์ด๋ก
return answer.join("")
}
solution("Zbcdefg") // 'gfedcbZ'
// ------ refactoring ------
function solution(s){
return Array.from(s) // ๋ฐฐ์ด๋ก ๋ง๋ค์ด์ค
.sort((a,b) => {
return a > b ? -1 : 1 // ๋ฌธ์์ด ์ซ์์ด ๋ชจ๋ ์ด ๋ฐฉ๋ฒ ์ฌ์ฉ ๊ฐ๋ฅํจ
}).join("")
}
solution("Zbcdefg") // 'gfedcbZ'