CSV import-export in Python

Question

I have finished a really short and small import / export script using Python 2.7, and now I would like to structure it using classes and methods where possible.

Could anybody give me some advice on what would be the best approach for this?

I haven't used any OOP because I would also like somebody to give me some best practices on how this should be done/structured.

from similarweb import ContentClient import csv FILE_OUT = 'similarweb/new_domains.csv' FILE_IN = 'similarweb/domains.csv' content_client = ContentClient("some_key") final_result = "" with open(FILE_IN, 'r') as csv_read_file: reader = csv.reader(csv_read_file) for i, line in enumerate(reader): url = ', '.join(str(e) for e in line) final_result += url + " " + (content_client.category(url)['Category']) + "\n" with open(FILE_OUT, 'w') as csv_write_file: csv_write_file.write(final_result) 

Answer 1

Rather than going down the OOP route, I would just split this out into a few functions:

import csv from similarweb import ContentClient CLIENT_KEY = 'some_key' FILE_IN = 'similarweb/domains.csv' FILE_OUT = 'similarweb/new_domains.csv' def extract_data(path, client): """Extract the data from the specified path using the client.""" lines = [] with open(path) as read_file: for line in csv.reader(read_file): url = ', '.join(line) # see note below lines.append(' '.join( (url, client.category(url)['Category']) )) return '\n'.join(lines) def save_data(path, data): """Save the data to the specified path.""" with open(path, 'w') as csv_write_file: csv_write_file.write(data) if __name__ == '__main__': save_data(FILE_OUT, extract_data(FILE_IN, ContentClient(CLIENT_KEY))) 

Per the documentation:

Each row read from the csv file is returned as a list of strings. No automatic data type conversion is performed.

so there is no need to explicitly convert to strings.

Answer 2

Writing classes is not an aim in itself, it is just a tool. Sometimes it's useful, sometimes it's not. I recommend the talk Stop Writing Classes.

Your code looks OK as it is, even if a few things can be improved. For instance, I'm not sure you use the value i so you probably don't need enumerate.