How to determine whether an element is in a list without case-insensitive in Python

In Python, you can determine whether an element is in a list, using the keyword in and not.

Examples are as follows:

If you need to output the appropriate information, you can use the IF statement, here do not repeat.

------------------------------------------------------------------------------------------Split Line---------------------------- -----------------------------------------------------------------------------------------------------------

Now there is a problem, I have a list of current_users, which is used to store the registered user name. There is also a list of new_users to store the user name that is requesting registration. If the user name of the application is determined to be registered?

The code is as follows:

The result of the operation is:

In the case of the default case, the five names have not been used, it is reasonable.

--------------------------------------------------------------------------------------------------------------- --Split Line--------------------------------------------------------------------------------------------------------------

Now case-sensitive:

The code is as follows:

The list parsing is used here, and a new all-lowercase list is generated, which is then compared. The results of the operation are as follows:

Forrest and Mike are not the same as the names of the existing usernames, but they are rejected for case-insensitive cases. Yes, there's nothing wrong.

PS: It has been previously useful to solve this problem with a dual for loop, but the output is a bit flawed, compared to a simpler list resolution.

Over

How to determine whether an element is in a list without case-insensitive in Python