Below I am using a filter with a lambda expression. Up until now, in my course, the "g" in lambda referred to a specific cell in a data frame. For instance, by_company.apply(lambda x: x*2). How does it recognize that it's supposed to be looking at the 'Units' column if g refers to a specific cell? I didn't know you could filter on a cell to obtain a column. I assume this may relate to my previous question about groupby objects.
by_company = sales.groupby('Company') by_company.filter(lambda g:g['Units'].sum() > 35)