Remove rows with empty lists from pandas data frame

To avoid converting to str and actually use the lists, you can do this:

df[df['donation_orgs'].map(lambda d: len(d)) > 0]

It maps the donation_orgs column to the length of the lists of each row and keeps only the ones that have at least one element, filtering out empty lists.

It returns

Out[1]: 
                            donation_context          donation_orgs
1  [In lieu of flowers , memorial donations]  [the research of Dr.]

as expected.