Regex: positive lookbehind

[snippsat]

1) do I have to place my variable (text_line) in quotation marks here?

Now is just a string 'text_lines',then this string is all that you search in
readlines() give back a list,and you can not pass a list to a regex search.
Have to loop over readlines() or ''.join() to string.

text_lines = f.readlines()
for line in text_lines:
    # Do regex stuff with line

When loop over many lines in regex can you re.finditer() for only load line bye line in memory,and avoid load the whole list.
Example.

import re

data = '''\
hi model choice : 999
model choice : abc
The green car had a model choice : Red color'''

pattern = re.compile(r"(?<=model choice :).*")
for match in pattern.finditer(data):
    print(match.group().strip())

Output:
999
abc
Red color