if 语句

users = ["woody", "Admin", "uni", "bob", "NEPTUNE"]
if users:## 确定列表不是空的
    for user in users:
        if user.lower() == "admin":
            print(f"Hello {user}, would you like to see a status report?")
        else:
            print(f"Hello {user}, thank you for logging in again.")
else:
    print("we need to find some users")

current_users = ["woody", "Admin", "uni", "bob", "NEPTUNE"]
new_users = ["Nepgear", "Neptune", "Uni", "ROM", "RAM"]

current_users_copy = [user.lower() for user in current_users]
## 创建副本
for user in new_users:
    if user.lower() in current_users_copy:
        print("You need to set another user name")
    else:
        current_users.append(user)
        print(f"Welcome {user}")

numbers = list(range(1, 12))
## 1- 10的序数
for number in numbers:
    if number == 1:
        print(f"{number}st")
    elif number == 2:
        print(f"{number}nd")
    elif number == 3:
        print(f"{number}rd")
    elif number < 11:
        print(f"{number}th")
    else:## else 是有风险的，可能有错误或恶意数据
        print(f"invalid number {number}.")

结果

Hello woody, thank you for logging in again.
Hello Admin, would you like to see a status report?
Hello uni, thank you for logging in again.
Hello bob, thank you for logging in again.
Hello NEPTUNE, thank you for logging in again.
Welcome Nepgear
You need to set another user name
You need to set another user name
Welcome ROM
Welcome RAM
1st
2nd
3rd
4th
5th
6th
7th
8th
9th
10th
invalid number 11.