How to compare two lists and print the difference in one list

I'm trying to extract usernames from a config file into a list and compare the usernames against another secure list of usernames. The config file looks like this this:

username Hilton privilege 15 password 0 $xxxxxxxxxxxxx
username gooduser password 0 $xxxxxxxxxxxxx
username jason secret 5 $xxxxxxxxxxxxx

The problem with the output is not a single list! (each user is in a list)

['Hilton']
['gooduser']
['jason']

I am reading the file into one single list. Then located the 'username' position and used enumerate to find the position

the_list = []

with open('config_file.txt', "r") as f:
    the_list = f.read().split()        
    print(the_list)
    find_keyword = 'username'

    secure_users = ['jason','test','admin']

for i,x in enumerate(the_list):   # search in the list
  if x=='username':               # for this keyword 'username'
     pos = i + 1                  # position of every username 

     print(the_list[pos].split())          # print all users.

#Compare secure_users[] vs the_list[] here

the expected output is a list like >> ['Hilton','gooduser','jason']

So that I can compare it against the secure_users list

Solution

Made some modification to your code,

the_list = []

with open('config_file.txt', "r") as f:
    the_list = f.read().split()        
    print(the_list)
find_keyword = 'username'

secure_users = ['jason','test','admin']

users_list = []
for i,x in enumerate(the_list):   # search in the list
    if x=='username':               # for this keyword 'username'
        pos = i + 1                  # position of every username 

        users_list.append(the_list[pos].split()[0])          # print all users
print(users_list)

Output:

['username', 'Hilton', 'privilege', '15', 'password', '0', '$xxxxxxxxxxxxx', 'username', 'gooduser', 'password', '0', '$xxxxxxxxxxxxx', 'username', 'jason', 'secret', '5', '$xxxxxxxxxxxxx']
['Hilton', 'gooduser', 'jason']

Another solution:(Best way)

with open('config_file.txt', 'r') as f:
    data = f.read().split()
    user_names = [data[i+1] for i,line in enumerate(data) if 'username' in line ]

Output:

['Hilton', 'gooduser', 'jason']