python - making a stacked barchart in pandas

Question

I would like to create a stacked bar plot from the following dataframe:

   VALUE     COUNT  RECL_LCC  RECL_PI
0      1  15686114         3        1
1      2  27537963         1        1
2      3  23448904         1        2
3      4   1213184         1        3
4      5  14185448         3        2
5      6  13064600         3        3
6      7  27043180         2        2
7      8  11732405         2        1
8      9  14773871         2        3

There would be 2 bars in the plot. One for RECL_LCC and other for RECL_PI. There would be 3 sections in each bar corresponding to the unique values in RECL_LCC and RECL_PI i.e 1,2,3 and would sum up the COUNT for each section. So far, I have something like this:

df = df.convert_objects(convert_numeric=True)    
sub_df = df.groupby(['RECL_LCC','RECL_PI'])['COUNT'].sum().unstack()
sub_df.plot(kind='bar',stacked=True)

However, I get this plot:

Any idea on how to fix it? I am doing something wrong with the groupby, but not sure of the solution

Answer 1

I've put data shown in stackpandas.dat. Given those data:

from pandas import *
import matplotlib.pyplot as plt

df = read_table("stackpandas.dat"," +",engine='python')

df = df.convert_objects(convert_numeric=True)
sub_df1 = df.groupby(['RECL_LCC'])['COUNT'].sum()
sub_df2 = df.groupby(['RECL_PI'])['COUNT'].sum()
sub_df = concat([sub_df1,sub_df2],keys=["RECL_LCC","RECL_PI"]).unstack()
sub_df.plot(kind='bar',stacked=True,rot=1)
plt.show()

... gives:

... which I think is what is sought.