Python integer input to corresponding command value

Question

I'm very new to python and was wondering if there was a way to convert a series of if statements to two corresponding lists?

To take something like this:

var = int(input("Enter a number: "))

if var == 1:
    print("One")
elif var == 2:
    print("Two")
elif var == 3:
    print("Three")
elif var == 4:
    print("Four")

And convert it into something like this:

commandnumber = [1, 2, 3, 4]
command = [("One", "Two", "Three", "Four")]

print(command[commandnumber.index(var)])

I don't know enough about to python to understand if this is even doable or not. I basically want an easier way for a user to input a number and receive a corresponding command (i.e. print or turtle.forward) depending on what number was inputted.

Thank you for your time.

The code that you've written would work as you expected. What's exactly your question? — Lie Ryan, Sep 29 '18 at 05:53
Though an easier way to do what you wanted to do is to use a dict rather than two arrays. — Lie Ryan, Sep 29 '18 at 05:55
@LieRyan There's a problem in the code. The list is only 1 long and the only element is a 4-tuple. — iBug, Sep 29 '18 at 05:55
@iBug good catch, but yes, just removing the extraneous round brackets would've made things work — Lie Ryan, Sep 29 '18 at 05:58
But what about just defining `command = ["One", "Two", "Three", "Four"]` and then printing `command[val-1]`? — toti08, Sep 29 '18 at 06:09

score 2 · Accepted Answer · answered Sep 29 '18 at 05:59

2

Using a dictionary might be a better way to do this.

outputs = {
    1: "One",
    2: "Two",
    3: "Three",
    4: "Four"
}

var = int(input("Enter a number: "))

print outputs[var]

answered Sep 29 '18 at 05:59

Bill

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score 0 · Answer 2 · answered Sep 29 '18 at 06:09

0

Try this, it is a little better and will not raise KeyError if get a bad option:

outputs = {
    1: "One",
    2: "Two",
    3: "Three",
    4: "Four",
    'default': 'bad option' 
}
try:
    var = int(input("Enter a number: "))
except ValueError:
    print(outputs.get('default'))        
else:
    print(outputs.get(var, 'bad option'))

Read here to learn more about try except else.

answered Sep 29 '18 at 06:09

Mehrdad Pedramfar

10,941
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probably don't need `else`, the line can be put directly after the input line - if a ValueError is raised, it won't be reached – iBug Sep 29 '18 at 06:24

score 0 · Answer 3 · answered Sep 29 '18 at 06:45

0

Another approach without using dictionaries could be:

command = ["One", "Two", "Three", "Four"]
try:
    print(command[val-1])
except:
    print('Invalid option')

answered Sep 29 '18 at 06:45

toti08

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Python integer input to corresponding command value

3 Answers3