Pandas如何根据索引值改变序列并保留其他序列值

import pandas as pd

data = {'A': [1, 2, 3, 4, 5],
        'B': [6, 7, 8, 9, 10],
        'C': [11, 12, 13, 14, 15]}
df = pd.DataFrame(data, index=['a', 'b', 'c', 'd', 'e'])

df.loc['b', 'A'] = 10

    A   B   C
a   1   6  11
b  10   7  12
c   3   8  13
d   4   9  14
e   5  10  15

df.loc['b', 'A'] = 10

    A   B   C
a   1   6  11
b  10   7  12
c   3   8  13
d   4   9  14
e   5  10  15