Defining variables and putting them in al list simultaneously

Question

For a game I’m creating i have an issue. I have a lot of cards, which amount I might wanna change later. So I have to assign variables:
amount_of_card_1 = 5
amount_of_card_2 = 7
amount_of_card_3 = 3
.
.
amount_of_card_100 = 6

Now I wanna create a list with all the variables I have just defined. Do I have to write them manually in a list? I’m looking for a easier way. Thanks for your help!!!

Answer 1

Why does that code not work?
i = 5
eval('a' +str(i)) = 7
print(a5)

Answer 2

You could use a dict too: amount = {1: 5, 2: 7, 3: 3} etc. and access the values like this: amount[2] # 7

If you already made 100 variables (I hope you didn't) and want to put all of their values in a list, you can do something like:

amount_of_card_1 = 5
amount_of_card_2 = 7
amount_of_card_3 = 3
(...)

amount = []

for i in range(1, 101):
amount.append(eval('amount_of_card_' + str(i)))

print(amount) # [5, 7, 3, (...)]

If you want the list to contain the variable names instead of their values, remove the eval(). Or do something like this:

amount = [l for l in locals() if l.startswith('amount_of_')]

print(amount) # ['amount_of_card_1', 'amount_of_card_2', 'amount_of_card_3', (...)]

Answer 3

Anna you don't need eval() for this because locals() returns a dict

for i in range(10):
exec('amount_of_' + str(i) + '=' + str(i))

dct = {key: value for key, value in locals().items() if key.startswith('amount_of_')}
print(dct)

clemens it doesn't work because you're trying to assign 7 to the result of a function. Use exec('a' + str(i) + '= 7')

Answer 4

Don't make separate variables. Put the numbers in a list in the first place.

amount_of_cards = [5, 7, 3, 6]

Be sure to check out the python lessons about lists, then you should be able to understand it better.

Answer 5

It checks locals() (where all your local variables are stored) for local variables that start with "amount_of_".

It should be possible to auto-generate a dictionary like this:

amount = {var: eval(var) for var in [l for l in locals() if l.startswith('amount_of_')]}

(Unfortunately, I can't test it at the moment, but it should work.)

Answer 6

Thanks for your help! Since its crucial for me to identify and change later easily the amount of each card a simple list is not very helpful.

A dictionary is a much better idea. Since i already defined my variables (shame on me) I’ll try your last solution. It looks up every input and checks whether it starts wirh amount_of?