Python Merge 2 Lists / Sql Join

If I have 2 lists or data frame (pandas) in python how do I merge / match / join them? For example: List / DF 1: Table_Name Table_Alias tab_1 t1 tab_2 t2 t

Solution 1:

You want an 'outer' merge:

In [9]:
df.merge(df1, how='outer')

Out[9]:
  Table_Name Table_Alias     Variable_Name
0      tab_1          t1             Owner
1      tab_1          t1          Owner_Id
2      tab_2          t2     Purchase_date
3      tab_3          t3  Maintenance_cost

It will match on overlapping columns from both dfs and return the union of the matching rows.

Solution 2:

I would simply use pd.merge(df1, df2, how='outer',on='alias')

df1 = pd.DataFrame({ "table_name":['tab1',"tab2","tab3"],"talias ['t1','t2','t3']})
df2 = pd.DataFrame({"talias":['t1',"t1","t2",'t3'], "vname,['Owner','Owner_Id','Purchase_date','Maintenance_cost']})


pd.merge(df1,df2,how='outer', on='talias')


Out:
    Table_Alias Table_Name  Variable_Name
0   t1  tab1    Owner
1   t1  tab1    Owner_Id
2   t2  tab2    Purchase_date
3   t3  tab3    Maintenance_cost