使用Pandas绘制包含列表的列 [英] Plotting a column containing lists using Pandas

问题描述

我有一个包含几列的数据框(df)，其中两列在每一行中存储一个列表:

I have a dataframe (df) containing several columns and two of them store a list in each row:

Index    list1                             list2
A   [ 0.09173306  0.12331911  0.20057651 ]  [ 0.3128322   0.27153913 ]
D   [ 0.03861522  0.10524985 ]              [ 0.37265687  0.48347806 ]
E   [ 0.02124905  0.01149118 ]              [ 0.04348405  0.17057435  0.37838683  0.37481453 ]

我想使用pandas内置plot函数将这些列表绘制为条形图.

I would like to plot these lists as bar graphs using pandas built-in plot function.

使用

df.list1.apply(lambda x:x[0]).plot(kind='bar', width=0.9, ax=bar_ax)

我可以绘制每个列表的第一个元素.但是，尝试

I can plot the first element of each list. However, trying

df.list1.plot(kind='bar', width=0.9, ax=bar_ax)

导致以下错误:

Empty 'DataFrame': no numeric data to plot

我想做的是，(1)将两个列表都绘制到一个图中，如下所示:

What I would like to do is, (1) plot both list into one single plot like so:

df[['list1','list2']].plot(kind='bar', width=0.9, ax=bar_ax)

并且(2)还将每个列表的第一个元素仅绘制到一个条形图中，我可以这样做:

And (2) also plot the first elements of each list only into one single bar plot, which I can do like this:

df.list1.apply(lambda x:x[0]).plot(kind='bar', width=0.9, ax=bar_ax, color='blue')
df.list2.apply(lambda x:x[0]).plot(kind='bar', width=0.9, ax=bar_ax, color='red')

但是，这导致条形图相互重叠(不堆叠！)-我想将它们分组.

However, this results in the bars being plotted on top of each other (not stacked!) - I want to have them grouped.

推荐答案

考虑此DF包含值的列表，如下所示:

Consider this DF containing values as lists as shown:

np.random.seed(42)
df = pd.DataFrame({'list1': np.random.randint(0, 10, (5,2)).tolist(), 
                   'list2': np.random.randint(0, 10, (5,3)).tolist()}, 
                   index=list('ABCDE'))

Q-1 将两个列表都绘制到一个图中:

取消堆叠DF，以使列名显示为索引，并使列表中的各个值呈现给各个系列对象.

Unstack the DF to make the column names appear as index and make individual values present in the list to individual series objects.

df_lists = df[['list1','list2']].unstack().apply(pd.Series)
df_lists.plot.bar(rot=0, cmap=plt.cm.jet, fontsize=8, width=0.7, figsize=(8,4))

Q-2 将每个列表的第一个元素仅绘制到一个单独的条形图中:

使用 DF.applymap 进行选择获取分组条形图所需列的第一个元素.

Use DF.applymap to select first element of the required columns to obtain the grouped bar plot.

df[['list1','list2']].applymap(lambda x: x[0]).plot.bar(rot=0, color=list('br'))

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