Javascript - 배열 내장함수 Test

배열이 주어졌을 때 10보다 큰 값의 갯수 구하기

• for문

function countBiggerThanTen(numbers) {
  let count = 0;
  for (let i = 0; i < numbers.length; i++) {
    if (numbers[i] > 10) {
      count += 1;
    }
  }
  return count;
}

const count = countBiggerThanTen([1, 2, 3, 5, 10, 20, 30, 40, 50, 60]);
console.log(count); // 5

• forEach

function countBiggerThanTen(numbers) {
  let count = 0;
  numbers.forEach( n => {
    if (n > 10) {
      count += 1;
    }
  });
  return count;
}

const count = countBiggerThanTen([1, 2, 3, 5, 10, 20, 30, 40, 50, 60]);
console.log(count); // 5

• filter

function countBiggerThanTen(numbers) {
  return numbers.filter(n => n > 10).length;
}

const count = countBiggerThanTen([1, 2, 3, 5, 10, 20, 30, 40, 50, 60]);
console.log(count); // 5

• reduce

function countBiggerThanTen(numbers) {
  return numbers.reduce((acc, cur) => {
    if ( cur > 10) {
      return acc += 1;
    } else {
      return acc;
    }
  }, 0);
}

const count = countBiggerThanTen([1, 2, 3, 5, 10, 20, 30, 40, 50, 60]);
console.log(count); // 5