python - pandas: exclude zeros when aggregating

Question

Consider some sample pandas dataset:

df = pd.DataFrame([[1, 2, 3],
                   [4, 5, 6],
                   [7, 8, 9],
                   [0, 0, 0]],
                   columns=['A', 'B', 'C'])

Now, I want to aggregate each column (say calculating the mean) where I want to exclude the zeros. I can see there is agg function that can be called but I could not figure out how to exclude the zeros when calculating the mean.

I know when mapping the columns, I need to somehow filter out the zeros but I cannot figure out how to include that in the call to the df.agg() function.

question from:https://stackoverflow.com/questions/65835868/pandas-exclude-zeros-when-aggregating

Answer 1

Replace the 0 with np.nan so you can call your agg function

df.replace(0,np.nan).agg(np.mean)