Return dataframe subset based on a list of boolean values

Question

I'm trying to slice a dataframe based on list of values, how would I go about this?

Say I have an expression or a list l = [0,1,0,0,1,1,0,0,0,1]

How to return those rows in a dataframe, df, when the corresponding value in the expression/list is 1? In this example, I would include rows where index is 1, 4, 5, and 9.

Answer 1

You can use masking here:

df[np.array([0,1,0,0,1,1,0,0,0,1],dtype=bool)]

So we construct a boolean array with true and false. Every place where the array is True is a row we select.

Mind that we do not filter inplace. In order to retrieve the result, you have to assign the result to an (optionally different) variable:

df2 = df[np.array([0,1,0,0,1,1,0,0,0,1],dtype=bool)]