To remove Chinese characters as features - I have created document-term matrix using TfIdfVectorizer, but just noticed the feature contains Chinese characters. Is it possible to remove them using Python's regex? 

I believe these characters are one of reason for lower prediction accuracy of my model.

Currently I use the below for pre-processing my data-

   # Pre-processing the data
    def text_preprocess( data ):
        # Changing to lower case
        data = data.lower()
        # Removing special characters
        data = re.sub("(\\d|\\W)+"," ",data)
        return data


Also, please note I used stopwords='english' in my TfidfVectorizer.

Please let me know if any information required. (New here, still learning)
If you want to remove non-English characters then this regex will work, by selecting characters not in a given ASCII range (0 to 122, you can adjust this since it will allow some special characters):

([^\x00-\x7A])+


So to remove those characters:

data = re.sub("([^\x00-\x7F])+"," ",data)