Join 2 dataframes in pandas using join-CodePudding

I have two data frames df1 and df2

df1

id     name
ada1  mike
ad23  tom
cev2  tim

df2

 id   month.   sales
 ada1. 1/11.    23
 ada1. 4/11.    34
 ad23. 3/12.    34
 cev2. 4/11.    32

I need :

 id   month.   sales name
 ada1. 1/11.    23.  mike
 ada1. 4/11.    34.  mike
 ad23. 3/12.    34.  tom
 cev2. 4/11.    32.  tim

I am struck between left join or right join, what should i use.

CodePudding user response：

Use pd.merge:

>>> df2.merge(df1, on='id', how='left')

     id month  sales  name
0  ada1  1/11     23  mike
1  ada1  4/11     34  mike
2  ad23  3/12     34   tom
3  cev2  4/11     32   tim

CodePudding user response：

Use map, since you are joining\merging on one column and returning one column.

df2['name'] = df2['id'].map(df1.set_index('id')['name'])

Map will outperform join\merge.