Unable to apply stop words in Pandas dataframe

[Bhaskar Dhariyal]

Hi everyone!

I have a dataset which I want to make model trainable. I ahve been trying to do some thing for past 2-3 days. 

Actually I wanted to clean 'desc' and 'keywords' column from the dataset. I am using NLTK to vectorize, than remove stopwords & alpha numeric values and do stemming. Moreover desc column also contain NULL values. But the solution I reached was on 2D list, to which I was not able to convert single pandas series, so that I could change change it word vector. 

Please tell me hoe to do this using Pandas, I searched lot in stackoverflow also but no results.

Link to dataset: https://drive.google.com/open?id=0B1D4AyluMGU0MGVkbWdvQkM3aUk

Thanks in advance

Bhaskar