Pandas colnames not found after grouping and aggregating

Question

Here is my data

threats = pd.read_csv('https://raw.githubusercontent.com/rfordatascience/tidytuesday/master/data/2020/2020-08-18/threats.csv', index_col = 0)

And here is my code -

df = (threats
.query('threatened>0')
.groupby(['continent', 'threat_type'])
.agg({'threatened':'size'}))

However df.columns only Index(['threatened'], dtype='object') is the result. That is, only the threatened column is displaying not the columns I have actually grouped by ie continent and threat_type although present in my data frame.

I would like to perform operation on the continent column of my data frame, but it is not displaying as one of the columns. For eg - continents = df.continent.unique() . This command gives me a key error of continent not found.

Answer 1

After groupby...pandas put the groupby columns in the index. Always reset index after doing groupby in pandas and don't do drop=True .

After your code.

df = df.reset_index()

And then you will get required columns.