列值取决于条件在 pandas 中的另一列

Question

我有一个示例数据：

datetime             temperature   season
2021-04-10 01:00:00.    10.        Heating season
2021-04-10 01:00:00.    26.        Heating season
2021-07-10 01:00:00.    16.        Cooling season
2021-07-10 01:00:00.    30.        Cooling season

我想创建一个名为 new_temperature 的新列：a) 如果温度列小于 18 并且季节是供暖季节，new_temperature 应该是 25 否则 18 如果是制冷季节. b) 如果温度列大于25且季节是制冷季节，则new_temperature列应为18，否则如果是采暖季节则应为22。

示例输出如下所示：

datetime             temperature   season.         new_temperature
2021-04-10 01:00:00.    10.        Heating season.    25
2021-04-10 01:00:00.    26.        Heating season.    22
2021-07-10 01:00:00.    16.        Cooling season.    18
2021-07-10 01:00:00.    30.        Cooling season.    18

Answer 1

np.select 有 4 个条件：

cond_1 = (df.temperature < 18) & (df.season == "Heating season")
cond_2 = (df.temperature < 18) & (df.season != "Heating season")
cond_3 = (df.temperature > 25) & (df.season == "Cooling season")
cond_4 = (df.temperature > 25) & (df.season != "Cooling season")

conditions = [cond_1, cond_2, cond_3, cond_4]
choices = [25, 18, 18, 22]

df["new_temperature"] = np.select(conditions, choices)

获得

               datetime  temperature          season  new_temperature
0  2021-04-10 01:00:00.         10.0  Heating season               25
1  2021-04-10 01:00:00.         26.0  Heating season               22
2  2021-07-10 01:00:00.         16.0  Cooling season               18
3  2021-07-10 01:00:00.         30.0  Cooling season               18

注意：由于您的条件不是相互排斥的，您可能希望为 np.select 提供一个 default 值作为最后一个参数。如果没有条件匹配，它将被放入结果中。

列值取决于条件在 pandas 中的另一列

Column values which depends on another column with conditions in pandas

python

numpy

pandas

data-science