[英]pandas: merge/combine/update two dataframes
I have 2 dataframes 我有2个数据帧
id nr lval
0 1 one 1
1 2 two 2
2 3 one 3
id nr rval
4 1 one 4
5 2 one 5
6 3 one 6
I need merge or combine these two dataframes and use column 'id' as a key. 我需要合并或组合这两个数据帧并使用列'id'作为键。 By collision (column 'nr') take the column from first dataframe.
通过碰撞(列'nr')从第一个数据帧中获取列。 Result should looks like this:
结果应如下所示:
id nr lval rval
0 1 one 1 4
1 2 two 2 5
2 3 one 3 6
As the shapes of the dfs are the same you can call combine_first
, the lhs df values supercede the rhs df hence you keep the nr column values: 由于dfs的形状相同,你可以调用
combine_first
,lhs df值取代rhs df,因此保留nr列值:
In [3]:
df.combine_first(df1)
Out[3]:
id lval nr rval
0 1 1 one 4
1 2 2 two 5
2 3 3 one 6
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