Am I misunderstanding the axis parameter? In one situation using .drop() the rows are affected by axis=0 and in another situation using .sum() the columns are affected by axis=0.
df = pd.DataFrame({"a":[1,4,7], "b":[2,5,8], "c":[3,6,9]})
df
a b c
0 1 2 3
1 4 5 6
2 7 8 9
# affects rows
df.drop([1], axis=0)
a b c
0 1 2 3
2 7 8 9
# affects columns
df.sum(axis=0)
a 12
b 15
c 18
dtype: int64
