Replace part of a string in a for loop

Question

I want to iterate through the list followers_list to edit each item.

followers_list = []

for follower in tweepy.Cursor(api.get_followers, screen_name='@'+screen_name, wait_on_rate_limit=True, count=200).items(9000): 
    followers_list.append([follower.profile_image_url_https])
    for i in followers_list:
        print(i.replace('normal', '400x400'))

Each item in the list is a URL like https://pbs.twimg.com/profile_images/1xxxxxxx/KLJHG-1367_normal.jpg that I want to change as https://pbs.twimg.com/profile_images/1xxxxxxx/KLJHG-1367_400x400.jpg

I'm returned the error :

Traceback (most recent call last):
  File "C:\Data\Mes documents\twitter\twitter_dl_pictures.py", line 30, in <module>
    url = [i.replace('normal', '400x400') for i in followers_list]
  File "C:\Data\Mes documents\twitter\twitter_dl_pictures.py", line 30, in <listcomp>
    url = [i.replace('normal', '400x400') for i in followers_list]
AttributeError: 'list' object has no attribute 'replace'

Answer 1

Use that instead:

for follower in tweepy.Cursor(api.get_followers, screen_name='@'+screen_name, wait_on_rate_limit=True, count=200).items(9000): 
    followers_list.append(follower.profile_image_url_https)

Explanation: Instead of adding the string to the list, you are adding a list containing the string.