通过列标题加入熊猫数据框

Question

I have two data frames (Actual and Targets) with followed headers:

print (df1)
    WorkWeek   Area  Actual
0     202001  South       5
1     202001  North       5
2     202001   West       6
3     202001   East       8
4     202002  South       7
5     202002  North       9
6     202002   West       6
7     202002   East       3
8     202003  South       5
9     202003  North      85
10    202003   West       5
11    202003   East      11
12    202004  South       2
13    202004  North       2
14    202004   West       2
15    202004   East       2


print (df2)
   WorkWeek  South  North  West  East
0    202001     60     90    70    80
1    202002     60     90    70    80
2    202003     60     90    70    80
3    202004     60     90    70    80

I want to have joined df(Actual_vs_Targets) by WW and Area

In case if i want to add more areas how should i act? Thank you!

Answer 1

Use DataFrame.melt with DataFrame.merge :

df22 = df2.melt('WorkWeek', var_name='Area', value_name='Target')
df = df1.merge(df22, on=['WorkWeek','Area'], how='left')

Or DataFrame.sem with DataFrame.join :

df22 = df2.set_index('WorkWeek').stack().rename_axis(['WorkWeek','Area']).rename('Target')
df = df1.join(df22, on=['WorkWeek','Area'])

---

print (df)
    WorkWeek   Area  Actual  Target
0     202001  South       5      60
1     202001  North       5      90
2     202001   West       6      70
3     202001   East       8      80
4     202002  South       7      60
5     202002  North       9      90
6     202002   West       6      70
7     202002   East       3      80
8     202003  South       5      60
9     202003  North      85      90
10    202003   West       5      70
11    202003   East      11      80
12    202004  South       2      60
13    202004  North       2      90
14    202004   West       2      70
15    202004   East       2      80