pandas - Pandas :根据字符串计数创建直方图

Question

我需要从包含值“低”，“中”或“高”的数据框列创建直方图。当我尝试执行通常的df.column.hist（）时，出现以下错误。

ex3.Severity.value_counts()
Out[85]: 
Low       230
Medium     21
High       16
dtype: int64

ex3.Severity.hist()


TypeError                                 Traceback (most recent call last)
<ipython-input-86-7c7023aec2e2> in <module>()
----> 1 ex3.Severity.hist()

C:\Users\C06025A\Anaconda\lib\site-packages\pandas\tools\plotting.py in hist_series(self, by, ax, grid, xlabelsize, xrot, ylabelsize, yrot, figsize, bins, **kwds)
2570         values = self.dropna().values
2571 
->2572         ax.hist(values, bins=bins, **kwds)
2573         ax.grid(grid)
2574         axes = np.array([ax])

C:\Users\C06025A\Anaconda\lib\site-packages\matplotlib\axes\_axes.py in hist(self, x, bins, range, normed, weights, cumulative, bottom, histtype, align, orientation, rwidth, log, color, label, stacked, **kwargs)
5620             for xi in x:
5621                 if len(xi) > 0:
->5622                     xmin = min(xmin, xi.min())
5623                     xmax = max(xmax, xi.max())
5624             bin_range = (xmin, xmax)

TypeError: unorderable types: str() < float()

Answer 1

ex3.Severity.value_counts().plot(kind='bar')

是您真正想要的。

当您这样做时：

ex3.Severity.value_counts().hist()

它会以错误的方式绕过轴，即尝试将y轴（计数）划分为bin，然后绘制每个bin中的字符串标签数。