how to join and sum columns (of different lengths) in pandas?
Question:
lets say I have the following dataframes
df1
name value
a 3
b 4
c 5
df2
name value
b 2
a 1
and I want to make a dataframe like this (there can be many value columns)
name value
a 4
b 6
c 5
Does anyone know how I would do this?
Answers:
You can temporarily set "name" as index:
df1.set_index('name').add(df2.set_index('name'), fill_value=0).reset_index()
Output:
name value
0 a 4.0
1 b 6.0
2 c 5.0
df2.set_index("name").reindex(df1.name).fillna(0).astype(int)+df1.set_index("name")
out：
value
name
a 4
b 6
c 5
lets say I have the following dataframes
df1
name value
a 3
b 4
c 5
df2
name value
b 2
a 1
and I want to make a dataframe like this (there can be many value columns)
name value
a 4
b 6
c 5
Does anyone know how I would do this?
You can temporarily set "name" as index:
df1.set_index('name').add(df2.set_index('name'), fill_value=0).reset_index()
Output:
name value
0 a 4.0
1 b 6.0
2 c 5.0
df2.set_index("name").reindex(df1.name).fillna(0).astype(int)+df1.set_index("name")
out：
value
name
a 4
b 6
c 5