如何对以下df进行切片,以使第二级!=二
在我的现实世界中,我的第二个级别是日期范围,我希望能够选择除了一个日期之外的所有内容。
来自MultiIndex/Advanced Indexing
In [1]: arrays = [['bar', 'bar', 'baz', 'baz', 'foo', 'foo', 'qux', 'qux'],
['one', 'two', 'one', 'two', 'one', 'two', 'one', 'two']]
In [2]: tuples = list(zip(*arrays))
In [4]: index = pd.MultiIndex.from_tuples(tuples, names=['first', 'second'])
In [16]: df = pd.DataFrame(np.random.randn(3, 8), index=['A', 'B', 'C'], columns=index)
In [38]: df = df.T
In [65]: df
Out[65]:
A B C
first second
bar one 0.895717 0.410835 -1.413681
two 0.805244 0.813850 1.607920
baz one -1.206412 0.132003 1.024180
two 2.565646 -0.827317 0.569605
foo one 1.431256 -0.076467 0.875906
two 1.340309 -1.187678 -2.211372
qux one -1.170299 1.130127 0.974466
two -0.226169 -1.436737 -2.006747
In [66]: df.xs('one', level='second')
Out[66]:
A B C
first
bar 0.895717 0.410835 -1.413681
baz -1.206412 0.132003 1.024180
foo 1.431256 -0.076467 0.875906
qux -1.170299 1.130127 0.974466
我很惊讶@pandas.pydata.org的文档如此糟糕。这些例子没有任何解释。这就像是由专家为那些对大熊猫的所有特征都有丰富经验的人编写的文件。
为什么文档中没有提供重新生成示例的代码?
从这个开始:
A B C
first second
bar one -0.350640 -1.761671 0.253923
two -0.036557 0.212322 0.537106
baz one -1.597584 -0.301356 -0.634428
two 2.340900 -0.356272 -0.985386
foo one 0.122753 -0.333827 -0.620175
two 0.423211 -0.570563 -1.245026
qux one -0.972814 -0.878836 -1.030892
two 0.312855 -0.191677 0.700006
df.iloc[df.index.get_level_values('second') != 'one' ]
A B C
first second
bar two -0.036557 0.212322 0.537106
baz two 2.340900 -0.356272 -0.985386
foo two 0.423211 -0.570563 -1.245026
qux two 0.312855 -0.191677 0.700006
df.iloc[df.index.get_level_values('second') != 'two' ]
A B C
first second
bar one -0.350640 -1.761671 0.253923
baz one -1.597584 -0.301356 -0.634428
foo one 0.122753 -0.333827 -0.620175
qux one -0.972814 -0.878836 -1.030892