In [2]: mi = DataFrame(dict(
A = np.arange(5).astype(np.float64),
B = np.arange(5).astype(np.int64)),
index=MultiIndex.from_tuples(tuple(zip(*[['bar','bar','baz','baz','baz'],['one','two','one','two','three']])),names=['first','second']))
In [3]: mi
Out[3]:
A B
first second
bar one 0 0
two 1 1
baz one 2 2
two 3 3
three 4 4
In [4]: mi.loc[('baz','two'),'B'] = -5
In [5]: mi
Out[5]:
A B
first second
bar one 0 0
two 1 1
baz one 2 2
two 3 -5
three 4 4
xs()
默认情况下创建数据的副本,因此要修改原始数据,应传递copy=False
:正如@phillipcloud指出的,
loc
更适合这份工作。如果将键指定为元组,也可以设置多个索引集。在相关问题 更多 >
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