如何根据另一个宽数据框中的匹配和范围值在一个长数据框中添加一列？

Question

df1 = pd.DataFrame(
      {'id': ['5AB', '5AB', '5AB', '5AB', '4CA', '01D', '01D', '4CA'],
       'Tin': [9.175, 0.792, 25.674999, 26.806999, 9.75, 7.51, 25.195, 21.316],
       'Tout': [20.792, 25.674999, 26.806999, 31.549, 21.316, 19.121, 28.669001, 26.337999],
       'name': ['FILIN', 'FILOUT', 'SEIN', 'SEOUT', 'FILIN', 'FIN', 'SEOUT', 'FILOUT']
      }) 

id  Tin         Tout        name
5AB 9.175       20.792      FILIN
5AB 20.792      25.674999   FILOUT
5AB 25.674999   26.806999   SEIN
5AB 26.806999   31.549      SEOUT
4CA 9.75        21.316      FILIN
01D 7.51        19.121      FIN
01D 25.195      28.669001   SEOUT
4CA 21.316      26.337999   FILOUT


df2 = pd.DataFrame(
      {'id': ['01D', '01D', '4CA', '4CA', '5AB', '5AB'],
       'T': [12.3, 27.5, 22.64, 23.2, 11.52, 2.34],
       'Type': ['Temp', 'Pres', 'Prox', 'Prox', 'Pres', 'Axe'],
       'val': [11.3, 1, 0, 2, 0.5, 23.1]
    })

id   T      Type        Val
01D  12.3   Temp        11.3
01D  27.5   Pres        1
4CA  22.64  Proximity   0
4CA  23.2   Proximity   2
5AB  11.52  Pres        0.5
5AB  2.34   Axe         23.1

I want to add the 'name' column to df2 where the value is dictated by matching 'id' in df1 and also whether the 'T' value in df2 is between 'Tin' and 'Tout' in df1. If there is no applicable range then set 'name' as None.

I am trying to get the following outcome:

id   T     Type         Val     name
01D  12.3   Temp        11.3    FIN
01D  27.5   Pres        1       SEOUT
4CA  22.64  Proximity   0       FILOUT
4CA  23.2   Proximity   2       FILOUT
5AB  11.52  Pres        0.5     FILIN
5AB  2.34   Axe         23.1    None

I can usually search my way out of these situations but not this time. Appreciate your help!

Answer 1

here is one way to do it

df2.merge(df1, on='id').query('T >= Tin & T<=Tout').drop(columns=['Tin', 'Tout'])

    id       T      Type    val     name
0   01D     12.30   Temp    11.3    FIN
3   01D     27.50   Pres    1.0     SEOUT
5   4CA     22.64   Prox    0.0     FILOUT
7   4CA     23.20   Prox    2.0     FILOUT
8   5AB     11.52   Pres    0.5     FILIN
9   5AB     11.52   Pres    0.5     FILOUT
13  5AB     2.34    Axe     23.1    FILOUT