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ランキングの実装完了 #437

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48 changes: 48 additions & 0 deletions app.js
Original file line number Diff line number Diff line change
@@ -1 +1,49 @@
'use strict';
const fs = require('fs');
const readline = require('readline');
const rs = fs.createReadStream('./popu-pref.csv');
const rl = readline.createInterface({ input: rs, output: {} });
const prefectureDataMap = new Map(); // key: 都道府県 value: 集計データのオブジェクト
rl.on('line', lineString => {
const columns = lineString.split(',');
const year = parseInt(columns[0]);
const prefecture = columns[1];
const popu = parseInt(columns[3]);
if (year === 2010 || year === 2015) {
let value = prefectureDataMap.get(prefecture);
if (!value) {
value = {
popu10: 0,
popu15: 0,
change: null
};
}
if (year === 2010) {
value.popu10 = popu;
}
if (year === 2015) {
value.popu15 = popu;
}
prefectureDataMap.set(prefecture, value);
}
});
rl.on('close', () => {
for (let [key, value] of prefectureDataMap) {
value.change = value.popu15 / value.popu10;
}
const rankingArray = Array.from(prefectureDataMap).sort((pair1, pair2) => {
return pair2[1].change - pair1[1].change;
});
const rankingStrings = rankingArray.map(([key, value]) => {
return (
key +
': ' +
value.popu10 +
'=>' +
value.popu15 +
' 変化率:' +
value.change
)
})
console.log(rankingStrings);
});