python - Numpy "where" with multiple conditions

Question

I try to add a new column "energy_class" to a dataframe "df_energy" which it contains the string "high" if the "consumption_energy" value > 400, "medium" if the "consumption_energy" value is between 200 and 400, and "low" if the "consumption_energy" value is under 200. I try to use np.where from numpy, but I see that numpy.where(condition[, x, y]) treat only two condition not 3 like in my case.

Any idea to help me please?

Thank you in advance

Answer 1

Try this: Using the setup from @Maxu

col         = 'consumption_energy'
conditions  = [ df2[col] >= 400, (df2[col] < 400) & (df2[col]> 200), df2[col] <= 200 ]
choices     = [ "high", 'medium', 'low' ]
    
df2["energy_class"] = np.select(conditions, choices, default=np.nan)


  consumption_energy energy_class
0                 459         high
1                 416         high
2                 186          low
3                 250       medium
4                 411         high
5                 210       medium
6                 343       medium
7                 328       medium
8                 208       medium
9                 223       medium