Stacked plot from pandas dataframe

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:

enter image description here

Any idea on how to obtain 2 columns (RECL_LCC and RECL_PI) instead of these 3?

Are all your dtypes numeric? You can do df = df.convert_objects(convert_numeric=True) to ensure the dtypes are ints/floats — EdChum
– EdChum, Commented Oct 31, 2014 at 20:56
Agree with @EdChum. Your code checks out on my side (I can plot it just fine). — WGS
– WGS, Commented Oct 31, 2014 at 20:56
thanks! that was needed, modified code to include the convert_objects statement. the plot still needs some work. — user308827
– user308827, Commented Oct 31, 2014 at 21:01

EdChum · Accepted Answer · 2014-10-31 21:17:37Z

2

So your problem was that the dtypes were not numeric so no aggregation function will work as they were strings, so you can convert each offending column like so:

df['col'] = df['col'].astype(int)

or just call convert_objects on the df:

df.convert_objects(convert_numeric=True)

answered Oct 31, 2014 at 21:17

EdChum

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6 Comments

user308827 Over a year ago

thanks! How did you know that they were not numeric?

EdChum Over a year ago

In your original post you had the error: *** TypeError: Empty 'DataFrame': no numeric data to plot now the only way you could have an empty dataframe after performing the aggregation is if none of your columns were numeric

user308827 Over a year ago

gotcha, makes sense now

EdChum Over a year ago

I don't know how you created the df but usually you can specify the dtype when loading data or when creating the df

user308827 Over a year ago

I was reading it using from_csv, that does not have a dtype, it seems like

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