How to retrieve a list using user input

Question

I want to ask the user which list they would like to access, then retrieve that list. I dont really have any code for this, because I'm currently just brainstorming. I couldn't really find a proper answer so here is a sample code I just made for the sake of explaining what I'm trying to do:

list1=[1, 2, 3, 4, 5]
list2=[6, 7, 8, 9, 10]
list3=['s', 'r', 't', 'd']

user_input=input('which list do you want to access')

I know that I can use if and elseif statements but the code I plan on making will have a large number of lists and I want a more efficient way to achieve this.

You could place the lists in a dictionary, as key, list pairs. This way a person identifies which list they want by the key (which could be 0, 1, 2, etc.) which then maps to the desired list in the dictionary. — DarrylG, May 28 '22 at 10:06
Do `mylist={ }` then `mylist["1"] = [1, 2, 3, 4, 5]` etc. Then ask the user for a number in the range 1..3 and get the desired list like this: `mylist[user_input]`. — BoarGules, May 28 '22 at 10:09
@azro i want to access it and use it for further purposes which could be printing yes — Mustafa, May 28 '22 at 10:10
Does this answer your question? [How do I create variable variables?](https://stackoverflow.com/questions/1373164/how-do-i-create-variable-variables) — BoarGules, May 28 '22 at 10:12

score 1 · Accepted Answer · answered May 28 '22 at 10:07

You can use dictionary to map input string to the right list

list1=[1, 2, 3, 4, 5]
list2=[6, 7, 8, 9, 10]
list3=['s', 'r', 't', 'd']

lists = {
    'list1': list1,
    'list2': list2,
    'list3': list3
}

user_input=input('which list do you want to access: ')
if user_input in lists:
    print('selected list:', lists[user_input])
else:
    print('no list matched')

score 1 · Answer 2 · answered May 28 '22 at 10:10

You can either use a nested list and access the lists by their index, or as already mentioned by @tax evader, use a dictionary to map the name of the list to the list itself:

# Using a list
def retrieve_list() -> list:
    lists = [
        [1, 2, 3, 4, 5]
        [6, 7, 8, 9, 10],
        ['s', 'r', 't', 'd']
    ]
    
    user_input = input("Which list do you want to access? ")
    try:
        return lists[int(user_input)-1]
    except:
        return None

# Using a dictionary
def retrieve_list() -> list:
    lists = {
        "1": [1, 2, 3, 4, 5]
        "2": [6, 7, 8, 9, 10],
        "3": ['s', 'r', 't', 'd']
    }
    
    user_input = input("Which list do you want to access? ")
    return lists.get(user_input, None)

How to retrieve a list using user input

2 Answers2