Get unique values from pandas series of lists

Question

I have a column in DataFrame containing list of categories. For example:

0                                                    [Pizza]
1                                   


        

Answer 1

Update using pandas 0.25.0+ with explode

df['category'].explode().value_counts()

Output:

Barbeque       3
Mexican        3
Fusion         2
Thai           2
American       2
Bars           2
Asian          2
Hawaiian       1
New            1
Brunch         1
Pizza          1
Traditional    1
Pubs           1
Korean         1
Pakistani      1
Burgers        1
Diners         1
Indian         1
Desserts       1
Halal          1
Nightlife      1
Breakfast      1
Name: Places, dtype: int64

And with plotting:

df['category'].explode().value_counts().plot.pie(figsize=(8,8))

Output:

---

For older verions of pandas before 0.25.0 Try:

df['category'].apply(pd.Series).stack().value_counts()

Output:

Mexican        3
Barbeque       3
Thai           2
Fusion         2
American       2
Bars           2
Asian          2
Pubs           1
Burgers        1
Traditional    1
Brunch         1
Indian         1
Korean         1
Halal          1
Pakistani      1
Hawaiian       1
Diners         1
Pizza          1
Nightlife      1
New            1
Desserts       1
Breakfast      1
dtype: int64

With plotting:

df['category'].apply(pd.Series).stack().value_counts().plot.pie()

Output:

Per @coldspeed's comments

from itertools import chain
from collections import Counter

pd.DataFrame.from_dict(Counter(chain(*df['category'])), orient='index').sort_values(0, ascending=False)

Output:

Barbeque     3
Mexican      3
Bars         2
American     2
Thai         2
Asian        2
Fusion       2
Pizza        1
Diners       1
Halal        1
Pakistani    1
Brunch       1
Breakfast    1
Burgers      1
Hawaiian     1
Traditional  1
Pubs         1
Korean       1
Desserts     1
New          1
Nightlife    1
Indian       1