How to count the values to prepare make stacked bar chart

Question

I'm wondering how to count the values in a column to make a stacked bar chart For example, the data is like below

I'd like to make a stacked bar chart with x="Main", which has the "Detail" values counts. All dtype is object.

What I tried to count the 'Detail' Values is

df['count'] = df['Detail'].value_counts()

But the count column has the value only NaN everytime.

Can you share your solution for this?

Answer 1

IIUC, use pd.crosstab and plot.bar:

pd.crosstab(index=df['Main'], columns=df['Detail']).plot.bar()

Output:

Input dataframe given as:

df = pd.DataFrame({'Main':[*'AAABBBC'],
                   'Detail':[*'aabbcda']})

Or stacked:

pd.crosstab(index=df['Main'], columns=df['Detail']).plot.bar(stacked=True)

Output: