Python: error in writing class

Question

I want to write func and add that to class. I use

import pandas as pd
import tldextract

domain = []
df = pd.DataFrame()
df['urls'] = ['ru.vk.com', 'eng.facebook.com', 'ru.ya.ru']
urls = df.urls.values.tolist()
class csv:
    def get_domain(self, list_url, list, df):
        self.list_url = list_url
        self.list = list
        self.df = df
        for i, url in enumerate(list_url):
            get_domain = tldextract.extract(url)
            subdomain = get_domain[0] + '.' + get_domain[1] + '.' + get_domain[2]
            if subdomain.startswith('.'):
                subdomain = subdomain[1:]
            elif subdomain.endswith('.'):
                subdomain = subdomain[:-1]
            elif subdomain.startswith('www.'):
                subdomain = subdomain[4:]
            list.append(subdomain)
        df['subdomain'] = list

df = csv()
df.get_domain(urls, domain, df)

I try to get domain from the urls, but I get error

AttributeError: csv instance has no attribute '__setitem__'

What I should change?

Answer 1

You named the variable that you use to create the csv instance df , same as the data frame item, by that making df refer to csv object and not panda dataframe. Then, when you try to call get domain , df refers to the class, that has no way to get a string indices, thus failing.

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In short - change the variable name in the last 2 rows, like

csv_df = csv()
csv_df.get_domain(urls, domain, df)

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By the way, It's not a mistake, but I'm pretty sure the last row on get_domain was supposed to be

self.df['subdomain'] = self.list

(Same goes for all variables all across the function, since you desire to change the class property and not the given variable).

And you shouldn't name a variable list or any other reserved keyword. Might cause issues.

Answer 2

I don't know what else should you change, but you most certainly should NOT use the get_domain variable inside the get_domain method. Start with this, and then see if it solves anything.

(the get_domain function is on the second line of the class, and the get_domain variable is on the 6th line of the class)

Edit: and one more thing, the code in the method has no relevance whatsoever to the values in the... let's call it test data. It might be wrong or it might be right, but you'd have no idea.