From 1450dcf0c1acf33a643519c359b80ffe92ef0a24 Mon Sep 17 00:00:00 2001
From: akira_ueno <akira_ueno@dwango.co.jp>
Date: Mon, 8 May 2023 13:52:24 +0900
Subject: [PATCH 1/2] =?UTF-8?q?=E3=83=A9=E3=83=B3=E3=82=AD=E3=83=B3?=
 =?UTF-8?q?=E3=82=B0=E3=81=AE=E5=AE=9F=E8=A3=85=E5=AE=8C=E4=BA=86?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 app.js | 44 +++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 43 insertions(+), 1 deletion(-)

diff --git a/app.js b/app.js
index ad9a93a..4e97388 100644
--- a/app.js
+++ b/app.js
@@ -1 +1,43 @@
-'use strict';
+"use strict";
+const fs = require("fs");
+const readline = require("readline");
+const rs = fs.createReadStream("./popu-pref.csv");
+const rl = readline.createInterface({ input: rs });
+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 = null;
+    if (prefectureDataMap.has(prefecture)) {
+      value = prefectureDataMap.get(prefecture);
+    } else {
+      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 (const [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);
+});

From 65c1cc7836a3a8f165f65f09286dfebaae9e21cf Mon Sep 17 00:00:00 2001
From: akira_ueno <akira_ueno@dwango.co.jp>
Date: Mon, 8 May 2023 13:57:57 +0900
Subject: [PATCH 2/2] =?UTF-8?q?change=20=E4=BA=BA=E3=81=8C=E6=B8=9B?=
 =?UTF-8?q?=E3=81=A3=E3=81=9F=E5=89=B2=E5=90=88=E3=81=AE=E3=83=A9=E3=83=B3?=
 =?UTF-8?q?=E3=82=AD=E3=83=B3=E3=82=B0?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 app.js | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/app.js b/app.js
index 4e97388..0ac6a53 100644
--- a/app.js
+++ b/app.js
@@ -34,10 +34,10 @@ rl.on("close", () => {
     value.change = value.popu15 / value.popu10;
   }
   const rankingArray = Array.from(prefectureDataMap).sort((pair1, pair2) => {
-    return pair2[1].change - pair1[1].change;
+    return pair1[1].change - pair2[1].change;
   });
-  const rankingStrings = rankingArray.map(([key, value]) => {
-    return `${key}: ${value.popu10}=>${value.popu15} 変化率: ${value.change}`;
+  const rankingStrings = rankingArray.map(([key, value], i) => {
+    return `${i + 1}位 ${key}: ${value.popu10}=>${value.popu15} 変化率: ${value.change}`;
   });
   console.log(rankingStrings);
 });