def register():
global username
username = raw_input("Enter a username: ").lower()
firstName = raw_input("Enter your first name: ").lower()
surname = raw_input("Enter your surname: ").lower()
age = raw_input("Enter your age: ")
yearGroup = raw_input("Enter your year group: ")
with open("users.txt", "a") as usersFile:
    for user in users:
        firstName = user[0]
        surname = user[1]
        age = user[2]
        yearGroup = user[3]
        usersFile.write(firstName + ';' + surname + ';' + age + ';' + yearGroup + ';' + 'n')

john;doe;13;9;
mary;smith;14;10;

with open('users.txt','r') as usersFile:
    usersList=[i.split(",") for i in usersFile.read().replace(" ","").splitlines()]

results = [str(score), username]
results.extend(usersList)
results = [results]

[[5, mary14, mary, smith, 14, 10][4, john13, john, doe, 13, 9]]

[['mary;smith;14;10'], [';'], ['john;doe;13;9']]
[['4', 'john13', ['mary;smith;14;10'], [';'], ['john;doe;13;9']]