python - How can I access a variable before I declare it?

Question

I am a total amateur when it comes to python and I have came across an issue:

if input() == existingUsername:
        print('Sorry, that username is taken, please try again:')

However, I need to access exisingUsername before it is declared, because I've defined it at the bottom of my code. I know you can do this in javascript with the let variable, but how can I do it in python?:

let existingUsername;
//code
existingUsername = 'name'

question from:https://stackoverflow.com/questions/65917558/how-can-i-access-a-variable-before-i-declare-it

Answer 1

You can't use a variable before declaring it. You could however use an empty string:

existingUsername = ""

# .
# .
# the rest of your program
# .
# .
username = input()
if username == existingUsername:
    print('Sorry, that username is taken, please try again:')
else:
    # assign new username here
    existingUsername = username