如何在pandas python中同时进行多个连接？

Question

I have data frame like below, where I need to join two tables and create the expected output as shown below and how can this be done

df1

Zone    Country

EU1      AT
EU1      BE
EU1      FR
AP2      IN
AP2      NZ

df2

Origin_Zone  Dest_zone  Key
  EU1          EU1        A
  AP2          EU1        B

Expected output

Org       Dest  Key
AT        AT     A
AT        BE     A
AT        FR     A
BE        AT     A
BE        BE     A
BE        FR     A
FR        AT     A
FR        BE     A
FR        FR     A
IN        AT     B
IN        BE     B
IN        FR     B
NZ        AT     B
NZ        BE     B
NZ        FR     B 

How to create the expected output in pandas

Answer 1

Use DataFrame.merge by both zones, then rename columns and select expected columns by list:

df = (df2.merge(df1, left_on='Origin_Zone',right_on='Zone')
         .merge(df1, left_on='Dest_zone',right_on='Zone')
         .rename(columns={'Country_x':'Org','Country_y':'Dest'})
         [['Org','Dest','Key']])
print (df)
   Org Dest Key
0   AT   AT   A
1   AT   BE   A
2   AT   FR   A
3   BE   AT   A
4   BE   BE   A
5   BE   FR   A
6   FR   AT   A
7   FR   BE   A
8   FR   FR   A
9   IN   AT   B
10  IN   BE   B
11  IN   FR   B
12  NZ   AT   B
13  NZ   BE   B
14  NZ   FR   B