Python list has none type elements even though filled with dataframe elements
Why do you even need to initialize the list with None values. Just create empty list and append your dataframes to it.
I initialize a list of length n using df_list = [None] * n. Then I have a for loop where I fill each element of df_list with a dataframe. Then, when I concat all these dataframes together using df = pd.concat(df_list, axis=0) I end up with fewer rows than expected, and upon further inspection I find that some elements of df_list are None type while others are dataframes. This is strange to me because in my for loop, I print the type of each value before filling it into df_list and they are all dataframes of the desired shape and columns as well. 
Wondering how, after running the loop, I can have None values in df_list when each value I filled in is a dataframe and not None. 
Any help here is appreciated - quite puzzled by this!