pandas 数据透视表错误：此时不支持 1 ndim Categorical
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Pivot table error:1 ndim Categorical are not supported at this time
提问by Lisa
My goal is to box-plot the 'score' by 'label', I don't care about "date" and "Cusip". I want to use 'pivot' to reshape the data, so that each Label is in one column and I can boxplot it.
我的目标是按“标签”绘制“分数”，我不关心“日期”和“Cusip”。我想使用“枢轴”来重塑数据，以便每个标签都在一列中，我可以对其进行箱线图。
date Cusip Label Score
663182 2015-07-31 00846UAG AAA 138.15
663183 2015-07-31 00846UAH AAA 171.93
663184 2015-07-31 00846UAJ AAA 175.67
663185 2015-07-31 023767AA BB 187.92
663186 2015-07-31 023770AA BB 176.25
t.pivot(index=['date','Cusip'],columns='Label',values='Score')
Errors shows:
错误显示：
NotImplementedError: > 1 ndim Categorical are not supported at this time
More details:
更多细节：
C:\Anaconda3\lib\site-packages\pandas\core\categorical.py in __init__(self, values, categories, ordered, name, fastpath, levels)
285 try:
--> 286 codes, categories = factorize(values, sort=True)
287 except TypeError:
C:\Anaconda3\lib\site-packages\pandas\core\algorithms.py in factorize(values, sort, order, na_sentinel, size_hint)
184 uniques = vec_klass()
--> 185 labels = table.get_labels(vals, uniques, 0, na_sentinel, True)
186
pandas\hashtable.pyx in pandas.hashtable.PyObjectHashTable.get_labels (pandas\hashtable.c:13921)()
ValueError: Buffer has wrong number of dimensions (expected 1, got 2)
采纳答案by Nickil Maveli
You really should be using pivot_tableas you have got duplicate entries in your datecolumn.
您真的应该使用，pivot_table因为您的date列中有重复的条目。
pd.pivot_table(df, values='Score', index=['date', 'Cusip'], columns=['Label']).boxplot()
回答by citynorman
As an alternative to .pivot_table(), which might do unwanted aggregations, you can do
作为.pivot_table()可能会进行不需要的聚合的替代方法，您可以执行
df.set_index(['date', 'Cusip','Label'])['Score'].unstack()
