如何通过 pandas 中位数对箱线图进行排序 [英] How to sort a boxplot by the median values in pandas

问题描述

我有一个数据帧outcome2，我可以通过以下方式生成分组的箱线图:

I've got a dataframe outcome2 that I generate a grouped boxplot with in the following manner:

In [11]: outcome2.boxplot(column='Hospital 30-Day Death (Mortality) Rates from Heart Attack',by='State')
        plt.ylabel('30 Day Death Rate')
        plt.title('30 Day Death Rate by State')
Out [11]:

我想做的是按照每个州的中位数对图进行排序，而不是按字母顺序.不知道如何去做.

What I'd like to do is sort the plot by the median for each state, instead of alphabetically. Not sure how to go about doing so.

推荐答案

要按中位数排序，只需计算中位数，然后对中位数进行排序，然后使用生成的Index来切片DataFrame:

To sort by the median, just compute the median, then sort it and use the resulting Index to slice the DataFrame:

In [45]: df.iloc[:10, :5]
Out[45]:
      AK     AL     AR     AZ     CA
0  0.047  0.199  0.969 -0.205  1.053
1  0.206  0.132 -0.712  0.111 -0.254
2  0.638  0.233 -0.907  1.284  1.193
3  1.234  0.046  0.624  0.485 -0.048
4 -1.362 -0.559  1.108 -0.501  0.111
5  1.276 -0.954  0.653 -0.175 -0.287
6  0.524 -1.785 -0.887  1.354 -0.431
7  0.111  0.762 -0.514  0.808  0.728
8  1.301  0.619  0.957  1.542 -0.087
9 -0.892  2.327  1.363 -1.537  0.142

In [46]: med = df.median()

In [47]: med.sort()

In [48]: newdf = df[med.index]

In [49]: newdf.iloc[:10, :5]
Out[49]:
      PA     CT     LA     RI     MO
0 -0.667  0.774 -0.999 -0.938  0.155
1  0.822  0.390 -0.014 -2.228  0.570
2 -1.037  0.838 -0.673  2.038  0.809
3  0.620  2.845 -0.523 -0.151 -0.955
4 -0.918  1.043  0.613  0.698 -0.446
5 -0.767  0.869 -0.496 -0.925 -0.374
6 -0.495  0.437  1.245 -1.046  0.894
7 -1.283  0.358  0.016  0.137  0.511
8 -0.018 -0.047 -0.639 -0.385  0.080
9 -1.705  0.986  0.605  0.295  0.302

In [50]: med.head()
Out[50]:
PA   -0.117
CT   -0.077
LA   -0.072
RI   -0.069
MO   -0.053
dtype: float64

结果图:

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