如何在两个数据框中使用不同的主键和外键列名称在 pandas 中进行 vlookup？

Question

Lets say we have two dataframes df and df1 with different column names like sku as primary key and sno as its foreign key:

Example1(df)
sku loc flag  
122  61 True 
123  61 True
113  62 True 
122  62 True 
123  62 False
122  63 False
301  63 True 

Example2(df1)
sno dept 
113 a
122 b
123 b
301 c 

I want to do a join or merge which looks like this:

Example3
sku loc flag   dept  
122  61 True   b
123  61 True   b
113  62 True   a
122  62 True   b
123  62 False  b
122  63 False  b
301  63 True   c

Unfortunately df.merge(df1, on='sku', how='left') and df['dept']=df.sku.map(df1.dept) doesn't work.

Example modified from: vlookup in Pandas using join

Answer 1

you have to set the left and right key

df1.merge(df2, right_on='sno',left_on='sku',how='left')


   sku  loc   flag  sno dept
0  122   61   True  122    b
1  123   61   True  123    b
2  113   62   True  113    a
3  122   62   True  122    b
4  123   62  False  123    b
5  122   63  False  122    b
6  301   63   True  301    c