Using a loop to make if statements

Question

In a project I am making, there is a list printed out like so

1. A
2. B
3. C
4. D

and so on, continuing up to 23. I am having having the user enter a selection based on the number, and then from there my program runs additional code, like so

entry = str(input())
if entry == '1':
    do_something
if entry == '2':
    do_something_else
if entry == '3':
    do_another_something

and this continues all the way until the 23rd selection. I realize I could type out each if statement, and brute force my way to the last if statement, but this feels quite repetitive, and I was wondering if there was a simplified solution to doing something like this (although I know this is not correct, simply an example)

for number in range(23):
    if entry == number:
        do_something

Perhaps a better explanation would be, I want to create a loop that creates if-statements for me.

Thanks for any help!

AChampion · Accepted Answer · 2017-03-13 01:41:44Z

1

You still need to describe the mapping from input to behaviour, you could do this as a dictionary. This assumes do_something... are functions that take no args:

dispatch = {
    '1': do_something,
    '2': do_something_else,
    '3': do_another_something,
    ...
}

entry = input()
dispatch[entry]()

If the functions were called do_something_<input> then you could do something dangerous without the mapping like:

fn = eval("do_something_{}".format(input()))
fn()

answered Mar 13, 2017 at 1:41

AChampion

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4 Comments

user7454726 Over a year ago

Since each if statement does something different, I would have to create a function for each one. In the end, I would still have to brute force my way through either functions or if statements, if my thinking is correct. Sadly I'm probably going to have to just stick with the if statements. Thanks for the help anyway!

AChampion Over a year ago

Without seeing what the do_something_XXX actually do, it's hard to help further - I'm assuming that they actual do something different dependent on the input. Not sure what you were hoping to be able to do. Still think the dispatch dict is cleaner than all the if statements.

cco Over a year ago

The dictionary is a better choice; it's cleaner (IMHO), and if any two choices have the same action, you can easily reuse a function.

user7454726 Over a year ago

The do_something would simply print out various information. I'm creating a program that allows me to sift through crafting formulas for a game, such as "a stick and a string makes a bow," or "2 sticks and 2 string makes a fishing rod."

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