Array Cardio

common

//특정 조건을 만족하는 새 배열 만들기 
  const inventors = [
    { first: 'Albert', last: 'Einstein', year: 1879, passed: 1955 },
    { first: 'Isaac', last: 'Newton', year: 1643, passed: 1727 },
    { first: 'Galileo', last: 'Galilei', year: 1564, passed: 1642 },
    { first: 'Marie', last: 'Curie', year: 1867, passed: 1934 },
    { first: 'Johannes', last: 'Kepler', year: 1571, passed: 1630 },
    { first: 'Nicolaus', last: 'Copernicus', year: 1473, passed: 1543 },
    { first: 'Max', last: 'Planck', year: 1858, passed: 1947 },
    { first: 'Katherine', last: 'Blodgett', year: 1898, passed: 1979 },
    { first: 'Ada', last: 'Lovelace', year: 1815, passed: 1852 },
    { first: 'Sarah E.', last: 'Goode', year: 1855, passed: 1905 },
    { first: 'Lise', last: 'Meitner', year: 1878, passed: 1968 },
    { first: 'Hanna', last: 'Hammarström', year: 1829, passed: 1909 }
  ];

  const people = [
    'Bernhard, Sandra', 'Bethea, Erin', 'Becker, Carl', 'Bentsen, Lloyd', 'Beckett, Samuel', 'Blake, William', 'Berger, Ric', 'Beddoes, Mick', 'Beethoven, Ludwig',
    'Belloc, Hilaire', 'Begin, Menachem', 'Bellow, Saul', 'Benchley, Robert', 'Blair, Robert', 'Benenson, Peter', 'Benjamin, Walter', 'Berlin, Irving',
    'Benn, Tony', 'Benson, Leana', 'Bent, Silas', 'Berle, Milton', 'Berry, Halle', 'Biko, Steve', 'Beck, Glenn', 'Bergman, Ingmar', 'Black, Elk', 'Berio, Luciano',
    'Berne, Eric', 'Berra, Yogi', 'Berry, Wendell', 'Bevan, Aneurin', 'Ben-Gurion, David', 'Bevel, Ken', 'Biden, Joseph', 'Bennington, Chester', 'Bierce, Ambrose',
    'Billings, Josh', 'Birrell, Augustine', 'Blair, Tony', 'Beecher, Henry', 'Biondo, Frank'
  ];

filter() - 특정 조건을 만족하는 새 배열 만들기

    
// Array.prototype.filter()
// 1. Filter the list of inventors for those who were born in the 1500's
// 1500 년대에 태어난 인물만 추려서 새로운 배열 만들기
const fifteen = inventors.filter(inventor => (inventor.year >= 1500 && inventor.year < 1600));

console.table(fifteen);

map() - 함수 결과를 모아 새 배열 만들기

 // 2. Give us an array of the inventor first and last names
 // 함수 결과를 모아 새 배열 만들기 (성 + 이름)
 const fullNames = inventors.map(inventor => `${inventor.first} ${inventor.last}`);
 console.log(fullNames);

sort() - 오름차나 내림차로 배열 정리하기

// 3. Sort the inventors by birthdate, oldest to youngest
// sort() 오름차순이나 내림차순으로 배열 정리하기 
const ordered2= inventors.sort((a, b) => a.year > b.year ? 1 : -1);
console.table(ordered2);

reudce() - 배열의 요소 값을 누적하여 계산하기

 // 4. How many years did all the inventors live?
 // reudce() - 배열의 요소 값을 누적하여 계산하기 (인물들이 산 햇수)
 const totalYears = inventors.reduce((total, inventor) => {
   return total + (inventor.passed - inventor.year);
 }, 0);

sort()

// 5. Sort the inventors by years lived
// sort() - 가장 오래 산 사람은? 
const oldest = inventors.sort(function(a, b) {
 const lastInventor = a.passed - a.year;
 const nextInventor = b.passed - b.year;
 return lastInventor > nextInventor ? -1 : 1;
});
console.table(oldest);

includes()

// 6. create a list of Boulevards in Paris that contain 'de' anywhere in the name
// includes() -이름에 'de'가 들어가는 사람만 모아서 새 배열로 만들기
const category = document.querySelector(".mw-category");
const categoryLinks = Array.from(category.querySelectorAll("a"));
const categoryLinksText = categoryLinks.map(link=>link.textContent);
const result = categoryLinksText.filter(text=>text.includes('de'));
// const result = de.filter(text=>text.indexOf("de") !== -1); //ES5
console.log(result);

sort()

// 7. sort Exercise
// Sort the people alphabetically by last name
// sort() - 이용하여 이름을 기준으로 알파벳순으로 나열
const alpha = people.sort((lastOne, nextOne) => {
  const [aLast, aFirst] = lastOne.split(', ');
  const [bLast, bFirst] = nextOne.split(', ');
  return aLast > bLast ? 1 : -1;
});
console.log(alpha);

reduce()

// 8. Reduce Exercise
// Sum up the instances of each of these
// reduce()를 활용해 인스턴스 개수세기 
const data = ['car', 'car', 'truck', 'truck', 'bike', 'walk', 'car', 'van', 'bike', 'walk', 'car', 'van', 'car', 'truck', 'pogostick'];

const transportation = data.reduce(function(obj, item) {
  if (!obj[item]) {
    obj[item] = 0;
  }
  obj[item]++;
  return obj;
}, {});

console.log(transportation);