根据单元格值将列添加到pandas数据框

Question

这是我拥有的东西：

list1_ = [("1","a","a1"),("1","b","b1"),("1","c","c"),("2","a","a2")]
df1 = pd.DataFrame(list1_,columns = ["user","col1","col2"])
list2_ = [("1","b","b2"),("1","a","a2"),("2","a","a3"),("1","c","c2")]
df2 = pd.DataFrame(list2_,columns = ["user","col1","col3"])

我想做的是让df2中的（user，col1）与df1配对并在df1中添加col3 ...基本上使df1：（user，col1，col2，col3）为相同的单元格值。 最终结果应如下所示：

list3_ = [("1","a","a1","a2"),("1","b","b1","b2"),("1","c","c","c2"), 
("2","a","a2","a3")]
df3 = pd.DataFrame(list3_,columns = ["user","col1","col2","col3"])

请注意：我从csv文件中读取df1，并使用list2_创建df2。因此，我有一些数据以list2_的形式而不是list1_的形式。因此，只想使用df1，list2_和/或df2。

Answer 1

使用pd.merge：

df1.merge(df2, on = ['user','col1'])

   user col1 col2 col3
0    1    a   a1   a2
1    1    b   b1   b2
2    1    c    c   c2
3    2    a   a2   a3