带有两个关键DataFrame的堆积条形图

Question

I have a dataframe with two keys. I'm looking to do a stacked bar plot of the number of items within key2 (meaning taking the count values from a fully populated column of data).

A small portion of the dataframe I have is:

Sector            industry                   
Basic Industries  Agricultural Chemicals         17
                  Aluminum                        3
                  Containers/Packaging            1
                  Electric Utilities: Central     2
                  Engineering & Construction     12
Name: Symbol, dtype: int64

Key1 is Sector, Key2 is Industry. I want the value in Symbol (the counted column to be represented as industry stackings) in a bar comprising Basic Industries.

I know if I do a df.reset_index I'll have a column with (non-unique) Sectors and Industries with an integer counter. Is there a way to simply assign the column 1,2,3 data to pandas plot or matplotlib to make a stacked bar chart?

Alternatively, is there a way to easily specify using both keys in the aforementioned dataframe?

I'm looking for both guidance on approach from more experienced people as well as help with the actual syntax.

Answer 1

I just added a new Sector to improve the example.

                                           Symbol
Sector            industry                           
Basic Industries  Agricultural Chemicals           17
                  Aluminum                          3
                  Containers/Packaging              1
                  Electric Utilities: Central       2
                  Engineering & Construction       22
Basic Industries2 Agricultural Chemicals            7
                  Aluminum                          8
                  Containers/Packaging             11
                  Electric Utilities: Central       7
                  Engineering & Construction        4

Assuming your dataframe is indexed by ["Sector", "industry"] you need first reset_index and then pivot your dataframe and finally make the stacked plot.

df.reset_index().pivot_table(index="industry", columns="Sector", values="Symbol").T.plot(kind='bar', stacked=True, figsize=(14, 6))

Answer 2

另一种方法，您可以使用以下方法，而不是reset_index ：

df.unstack().Symbol.plot(kind='bar', stacked=True)