回答編集履歴
2
修正
answer
CHANGED
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@@ -7,4 +7,5 @@
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7
7
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df = pd.read_csv("sample.csv", header=None, parse_dates=[0])
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8
8
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df[2] = np.where(df[0] <= "2020-06-20T14:17:34", 40, 20)
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9
9
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df.to_csv("output.csv")
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10
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+
print(df)
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10
11
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```
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1
修正
answer
CHANGED
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@@ -1,46 +1,10 @@
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1
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-
1列目が日付だと仮定すると、read_csv() で読み込んだあとに `df[
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1
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+
1列目が日付だと仮定すると、read_csv() で読み込んだあとに `df[0] <= 日付を表す文字列` が成り立つ行は40、そうでない行は20を numpy.where() で代入すればよいです。
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2
2
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3
3
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```python
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4
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+
import numpy as np
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5
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import pandas as pd
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6
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+
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4
7
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df = pd.read_csv("sample.csv", header=None, parse_dates=[0])
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5
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-
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6
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-
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8
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+
df[2] = np.where(df[0] <= "2020-06-20T14:17:34", 40, 20)
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7
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-
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9
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+
df.to_csv("output.csv")
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8
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-
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9
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-
df = df[(start < df[0]) & (df[0] <= end)]
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10
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print(df)
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11
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```
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12
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-
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13
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csv のサンプル
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14
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-
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15
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```
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16
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2020-10-01,0
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17
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2020-10-02,1
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2020-10-03,2
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19
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2020-10-04,3
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20
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2020-10-05,4
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21
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2020-10-06,5
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22
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2020-10-07,6
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2020-10-08,7
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24
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2020-10-09,8
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25
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2020-10-10,9
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26
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2020-10-11,10
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27
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2020-10-12,11
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28
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2020-10-13,12
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29
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2020-10-14,13
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30
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2020-10-15,14
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2020-10-16,15
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2020-10-17,16
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2020-10-18,17
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34
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2020-10-19,18
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2020-10-20,19
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2020-10-21,20
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2020-10-22,21
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2020-10-23,22
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2020-10-24,23
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40
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2020-10-25,24
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41
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2020-10-26,25
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42
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2020-10-27,26
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43
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2020-10-28,27
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2020-10-29,28
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45
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2020-10-30,29
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46
10
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```
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