回答編集履歴
3
test
CHANGED
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@@ -11,3 +11,35 @@
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11
11
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12
12
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# [0, 0, 0, 0, 1, 2, 3, 0, 0, 1, 2, 0, 0]
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13
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```
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14
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+
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15
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+
### 追記
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16
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17
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```julia
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18
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$ julia
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19
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help?> zip
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20
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search: zip
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21
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22
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zip(iters...)
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23
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24
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Run multiple iterators at the same time, until any of them is exhausted.
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25
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The value type of the zip iterator is a tuple of values of its subiterators.
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26
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```
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27
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+
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28
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`zip()`(イテレータ)を利用する方が3倍程度速く、メモリ使用量も少ないです。
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29
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```julia
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30
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using DataFrames
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31
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import ShiftedArrays: lag
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32
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using BenchmarkTools
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33
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34
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test = DataFrame(a=[1,2,3,2,2,2,2,4,5,5,5,6,7])
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35
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+
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36
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@btime accumulate((acc, i) -> i ? acc+1 : 0,
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37
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test.a .== lag(test.a, default=test.a[1]-1))
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@btime accumulate((acc, (i, j)) -> i==j ? acc+1 : 0,
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39
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zip(test.a, lag(test.a, default=0));
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40
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init=test.a[1]-1)
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41
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42
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# 3.859 μs (22 allocations: 1.59 KiB)
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43
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# 1.304 μs (8 allocations: 416 bytes)
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44
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```
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45
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+
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2
test
CHANGED
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@@ -5,8 +5,8 @@
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5
5
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6
6
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test = DataFrame(a=[1,2,3,2,2,2,2,4,5,5,5,6,7])
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7
7
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8
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-
newList = accumulate((acc,
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8
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newList = accumulate((acc, i) -> i ? acc+1 : 0,
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9
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-
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9
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test.a .== lag(test.a, default=test.a[1]-1));
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10
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println(newList)
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11
11
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# [0, 0, 0, 0, 1, 2, 3, 0, 0, 1, 2, 0, 0]
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1
test
CHANGED
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@@ -5,7 +5,7 @@
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5
5
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6
6
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test = DataFrame(a=[1,2,3,2,2,2,2,4,5,5,5,6,7])
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7
7
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8
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-
newList = accumulate((acc, i) -> i
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8
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+
newList = accumulate((acc, (i, j)) -> i==j ? acc+1 : 0, zip(test.a, lag(test.a, default=0));
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9
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init=test.a[1]-1)
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10
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println(newList)
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11
11
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