回答編集履歴
2
letでなくてconstに直した...ねむい
answer
CHANGED
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@@ -1,20 +1,18 @@
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1
1
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new Map()と分割代入の練習で作ってみました。
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2
2
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```js
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3
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-
let data = [["a", "b", 10], ["a", "b", 20], ["a", "c", 30], ["a", "c", 40], ["a", "d", 50], ["a", "b", "c",50], ["a", "b", "c",50]];
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3
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+
let data = [["a", "b", 10], ["a", "b", 20], ["a", "c", 30], ["a", "c", 40], ["a", "d", 50], ["a", "b", "c", 50], ["a", "b", "c", 50]];
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4
4
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//[["a","b",30],["a","c",70],["a","d",50];
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5
5
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6
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-
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6
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+
const aggregate = new Map();
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7
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data.forEach(keys_value => {
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8
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-
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8
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+
const value_keys = Array.from(keys_value);
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9
9
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value_keys.unshift(value_keys.pop());
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10
10
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const [value, ...keys] = [...value_keys];
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11
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-
aggregate.set(JSON.stringify(keys), (aggregate.get(JSON.stringify(keys)) || 0)+value);
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11
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+
aggregate.set(JSON.stringify(keys), (aggregate.get(JSON.stringify(keys)) || 0) + value);
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});
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const result = [...aggregate.entries()].map(v => [...JSON.parse
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const result = [...aggregate.entries()].map(v => [...JSON.parse(v[0]), v[1]]); //[ [ "a", "b", 30 ], [ "a", "c", 70 ], [ "a", "d", 50 ], [ "a", "b", "c", 100 ] ]
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15
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console.log(result);
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16
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-
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17
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-
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18
16
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```
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19
17
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20
18
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```json
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1
keysの方がしっくり来る
answer
CHANGED
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@@ -4,16 +4,17 @@
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4
4
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//[["a","b",30],["a","c",70],["a","d",50];
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5
5
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6
6
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let aggregate = new Map();
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7
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-
data.forEach(
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7
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+
data.forEach(keys_value => {
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8
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-
let
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8
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let value_keys = Array.from(keys_value);
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9
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-
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9
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value_keys.unshift(value_keys.pop());
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10
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-
const [value, ...
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10
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const [value, ...keys] = [...value_keys];
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11
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-
aggregate.set(JSON.stringify(
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11
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aggregate.set(JSON.stringify(keys), (aggregate.get(JSON.stringify(keys)) || 0)+value);
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12
12
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});
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const result = [...aggregate.entries()].map(v => [...JSON.parse (v[0]),v[1]]); //[ [ "a", "b", 30 ], [ "a", "c", 70 ], [ "a", "d", 50 ], [ "a", "b", "c", 100 ] ]
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15
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console.log(result);
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16
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17
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+
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18
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```
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18
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19
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```json
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