pandas 版本之间的MultiIndex/Shaping差异 [英] MultiIndex/Reshaping differences between Pandas versions
问题描述
我有一个使用以下代码的DataFrame:
I have a DataFrame using the following code:
import pandas as pd
import numpy as np
index = pd.DatetimeIndex(['2017-05-04', '2017-05-05', '2017-05-08', '2017-05-09',
'2017-05-10'], dtype='datetime64[ns]',name = 'date', freq='B')
columns = pd.MultiIndex(levels=[['HSBA LN Equity', 'UCG IM Equity', 'ISP IM Equity'], ['LAST PRICE', 'HIGH', 'LOW']],
labels=[[0, 0, 0, 1, 1, 1, 2, 2, 2], [0, 1, 2, 0, 1, 2, 0, 1, 2]])
data = np.array([[ 663.8, 672.5, 661.1, 15.97, 16.02, 15.49, 2.76, 2.768, 2.694],
[ 658.6, 663.9, 656.0, 16.22, 16.48, 15.77, 2.842, 2.868, 2.77 ],
[ 660.6, 664.1, 658.9, 16.01, 16.49, 15.94, 2.852, 2.898, 2.826],
[ 664.9, 669.2, 662.5, 15.90, 16.41, 15.90, 2.848, 2.898, 2.842],
[ 670.9, 673.4, 663.8, 16.09, 16.15, 15.59, 2.85, 2.888, 2.802]])
df = pd.DataFrame(data, columns=columns, index = index)
输出看起来像这样:
HSBA LN Equity UCG IM Equity \
LAST PRICE HIGH LOW LAST PRICE HIGH LOW
date
2017-05-04 663.8 672.5 661.1 15.97 16.02 15.49
2017-05-05 658.6 663.9 656.0 16.22 16.48 15.77
2017-05-08 660.6 664.1 658.9 16.01 16.49 15.94
2017-05-09 664.9 669.2 662.5 15.90 16.41 15.90
2017-05-10 670.9 673.4 663.8 16.09 16.15 15.59
ISP IM Equity
LAST PRICE HIGH LOW
date
2017-05-04 2.760 2.768 2.694
2017-05-05 2.842 2.868 2.770
2017-05-08 2.852 2.898 2.826
2017-05-09 2.848 2.898 2.842
2017-05-10 2.850 2.888 2.802
由于当我使用df = df.stack(0)时从0.19.2升级到Pandas 0.20.1，因此输出如下所示:
Since upgrading to Pandas 0.20.1 from 0.19.2 when I use df = df.stack(0) the output looks like this:
HIGH LAST PRICE LOW
date
2017-05-04 HSBA LN Equity 672.500 663.800 661.100
UCG IM Equity 2.768 2.760 2.694
ISP IM Equity 16.020 15.970 15.490
2017-05-05 HSBA LN Equity 663.900 658.600 656.000
UCG IM Equity 2.868 2.842 2.770
ISP IM Equity 16.480 16.220 15.770
2017-05-08 HSBA LN Equity 664.100 660.600 658.900
UCG IM Equity 2.898 2.852 2.826
ISP IM Equity 16.490 16.010 15.940
2017-05-09 HSBA LN Equity 669.200 664.900 662.500
UCG IM Equity 2.898 2.848 2.842
ISP IM Equity 16.410 15.900 15.900
2017-05-10 HSBA LN Equity 673.400 670.900 663.800
UCG IM Equity 2.888 2.850 2.802
ISP IM Equity 16.150 16.090 15.590
列已更改顺序，股票价格不再与正确的股票代码匹配.
The columns have changed order and the equity prices no longer match the correct tickers.
这是一个错误吗?
推荐答案
这绝对是一个错误，并且由于我的两个团队大量使用MultiIndex列并对其进行堆叠有点吓人.在您的问题#16323 中进行跟踪并进行了公关(#16325 ).
This was definitely a bug, and since two of my teams make heavy use of MultiIndex columns and stacking it was a little scary. Tracked it down in your issue #16323 and made a PR (#16325).
它已被合并到master中，并将成为当前计划于2017年6月13日发布的0.20.2 bugfix版本的一部分.
This has already been merged into master and will be part of the 0.20.2 bugfix release, currently scheduled for June 13, 2017.
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