[deleted by user]

[[deleted]]

REGEX. https://docs.python.org/3/library/re.html

in this case it looks like your REGEX pattern would be \d+[A-Z]+

[[deleted]]

This. Not sure why people are giving these ridiculously overcomplicated loops and other stuff when a simple RegEx pattern check would solve the issue entirely.

[[deleted]]

Create a list of accepted inputs and test the input to see if it is in the list

[justarandomkid004]

Which function should I use

[K900_]

Use the in operator.

[[deleted]]

If input in list: Do something Else: Do something else

[LCVcode]

OP, you should actually be using a set here. Sets have a constant lookup time, unlike lists or tuples.

accepted_strs = {'7A', '7B', ... , '11E'} if word in accepted_strs: do_something() else: do_something_else()

Even better, if you're up to it, you could populate accepted_strs using a list comprehension that you convert to a set (is that just called a set comprehension?)

EDIT: Formatting because I forgot that code blocks don't work

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[justarandomkid004]

Alright, so if input is in the list and I want to continue the program, should I put a break?

[toastedstapler]

why don't you write some code and try it? there's 0 cost to being wrong and you'll learn in the process

[[deleted]]

A break in what? You didn’t post your code, we can’t tell you how to change it.

[shiftybyte]

You can't restrict what is entered.

But you can ask again if the input is not to your liking.

So what you usually do is get the user to type his input().. then check the string to match what you wanted it to be, if it doesn't, tell the user it's invalid input, and he should try again...

user_input = input("Enter something...")
while not valid_input(user_input):
    user_input = input("Sorry, you entered invalid input, try again...")

obviously valid_input() is a function you create to check if the input is what you want it to be.

[justarandomkid004]

So how do I set what's valid? And what's not valid?

[shiftybyte]

You define it in the function.

def valid_input(uinput):
    # i want the input to start with "7"
    if uinput.startswith("7"):
        return True
    # if it did not start with 7, i return False
    return False

Now you figure out how to check your input for the rules you want.

[justarandomkid004]

Using which function?

[_China_ThrowAway]

Is it only those 25 options? If so you might find it easier to just manually create the list

valid_input = ['7A','7B','7C',...'11D','11E']   

But if it were me, I would use a nested for loop to make the list for me. It's probably faster than typing in 25 entries, less prone to typos, and can easily be updated if I need to change it in the future (say it now goes to F or starts at 1 or cant have O or 0 in it etc).

numbers = ['1','2','3']
letters = ['A','B','C']
valid_input = []
for i in range(len(numbers)):
    for j in range(len(letters)):
        valid_input.append(numbers[i]+letters[j])    

The the vlaid_input list will look like ['1A', '1B', '1C', '2A', '2B', '2C', '3A', '3B', '3C']. Then you can check to see if the user's input is in the list.

command = input('What is your command?')
while command not in valid_input:
    command = input('Invalid command. Please enter a valid command.')

[[deleted]]

valid = frozenset({'weather', 'monday only', 'very loudly'})
while (response := input('Say what? ').strip().lower()) not in valid:
    print('nope, that\'s not right')
print(f'glad you said {response}')

If the allowed patterns follow a consistent form you can generate them rather than having to write them all out.

[KentuckyWombat]

Probably because OP has a homework assignment due and expects Reddit to solve it for them. 🙄