JavaScript에서의 for문, filter(조건 만족하는 값 빼내기)

기본 for문

 

let numbers= [1, 2, 3, 4, 5, 6];
 let fruits= ["사과", "바나나", "수박", "포도", "파인애플"];
 for(let i= 0; i< numbers.length; i++) {
 console.log(numbers[i]);
 }
 for(let i= 0; i< fruits.length; i++) {
 console.log(fruits[i]);
 }

 

for of 반복문 

let numbers= [1, 2, 3, 4, 5, 6];
 let fruits= ["사과", "바나나", "수박", "포도", "파인애플"];
 let numbersLength= numbers.length;
 let fruitsLength= fruits.length;
 for(let number of numbers) {
 console.log(number);
 }
 for(letfruitoffruits) {
 console.log(fruit);
 }

 

forEach

let numbers = [1, 2, 3, 4, 5, 6];
 let fruits = ["사과", "바나나", "수박", "포도", "파인애플"];
 numbers.forEach(function (number, index, array) {
 console.log(number, index, array);
 });
 numbers.forEach((number, index, array) => {
 console.log(number, index, array);
 });
 fruits.forEach(function (fruit, i, arr) {
 console.log(fruit, i, arr);
 });
 fruits.forEach((fruit, i, arr) => {
 console.log(fruit, i, arr);
 })

 

filter : 조건에 부합하는 요소만을 반환 

 

let numbers= [1, 2, 3, 4, 5, 6];
 let arr;
 arr= numbers.filter(function(num) {
 return num> 3;
 });
 console.log(arr);
 const words= ['spray', 'limit', 'elite', 'exuberant', 'destruction', 'present'];
 const result= words.filter(word => word.length > 6); //글자 수가 6자리 인 녀석 반환
 console.log(result)