자바스크립트 30 4번째 과제 중...
<배열>
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",
];
const data = [
"car",
"car",
"truck",
"truck",
"bike",
"walk",
"car",
"van",
"bike",
"walk",
"car",
"van",
"car",
"truck",
];
inventors
에서 1500년대 출생자의 리스트만 구해라. (filter)const fifteen = inventors.filter((inventor) => {
if (inventor.year >= 1500 && inventor.year < 1600) {
return true;
} else {
return false;
}
});
// 또는
const fifteen = inventors.filter((inventor) => inventor.year >= 1500 && inventor.year < 1600);
inventors
에서 이름과 성만 구해라 (map)const inventorsName = inventors.map((inventor) => {
const name = `${inventor.first} ${inventor.last}`;
return name;
});
inventors
에서 출생 순으로 정렬해라 (sort)
const sortedInventorsBybirth = inventors.sort((a, b) => {
return a.year > b.year ? 1 : -1;
});
// 또는
const sortedInventorsBybirth = inventors.sort((a, b) => a.year - b.year);
inventors
의 나이 합은? (reduce)const sum = inventors.reduce((acc, cur) => {
return acc + cur.passed - cur.year;
}, 0);
inventors
의 나이가 많은사람 > 적은사람 순으로 정렬 (sort)
const old = inventors.sort((a, b) => {
const lastGuy = a.passed - a.year;
const nextGuy = b.passed - b.year;
return nextGuy - lastGuy;
// return lastGuy > nextGuy ? -1 : 1;
});
const alpha = people.sort((lastOne, nextOne) => {
// split() 은 배열을 반환함, 구조분해할당
const [aLast, aFirst] = lastOne.split(", ");
const [bLast, bFirst] = nextOne.split(", ");
return aLast > bLast ? 1 : -1;
// return aLast - bLast 는 X
});
//또는
const alpha = people.sort();
const hobby = data.reduce((obj, item) => {
if (!obj[item]) {
obj[item] = 0;
}
obj[item]++;
return obj;
}, {});
// {car: 5, truck: 3, bike: 2, walk: 2, van: 2}