Still do not get how Python iterates over a file

[tester_V]

That is why I'm coming back to this forum, you guys sharing knowledge and teaching, people like me, how to write a better code and you do it without an attitude.

To supuflounder:
you are right some of you are over 50, I have to tell some of us are over 60
So you just a kid to me

Thank you for coaching!
Thank you for the code!
Love you all!

[Gribouillis]

Here is simpler and more scalable version (simple is better than complex)

import io

file1 = io.StringIO("""\
ZPM911
ZPM1912
ZPM1919
ZPM4555
ZPM4556
ZPM4557
""")

list_2 = ['ZPM911,UP,DOWN','ZPM1912,UP,UP','ZPM1919,DOWN,DOWN']
set_2 = set(el.split(',', 1)[0] for el in list_2)

for line in file1:
    el = line.strip()
    if el in set_2:
        print(f'Matched ++++++ {el}')
    else:
        print(f'Not matched -- {el}')

[tester_V]

Well, I hope someday I'll be able to do the same you do...

Thank you again!
I really appriciate it!

[naughtyCat]

is this what u want?

list_1 = ['ZPM911', 'ZPM1912', 'ZPM1919', 'ZPM4555', 'ZPM4556', 'ZPM4557']
list_2 = ['ZPM911,UP,DOWN', 'ZPM1912,UP,UP', 'ZPM1919,DOWN,DOWN']

for item in list_1:
    if item not in [i.split(",")[0] for i in list_2]:
        print(f" Not Matched -- {item}")
    else:
        print(f" Matched ++++++ {item}")

Output:
 Matched ++++++ ZPM911
 Matched ++++++ ZPM1912
 Matched ++++++ ZPM1919
 Not Matched -- ZPM4555
 Not Matched -- ZPM4556
 Not Matched -- ZPM4557