How to refer to variable based on a number in Python?

Question

I have a program in Python 2.7 where I'm trying to refer to some variable based on a number a user inputs. I have the following:

p1 = "foo1"
p2 = "foo2"
p3 = "foo3"
p4 = "foo4"
p5 = "foo5"
p6 = "foo6"
p7 = "foo7"
k = raw_input('Enter number')

Clearly, having if statements on k would be redundant. Is there a more elegant way for my program to, given k, refer to the variable pk? For example, if k=2, the program would find variable p2.

I think you need [list](https://docs.python.org/2/tutorial/datastructures.html) — Yevhen Kuzmovych, Jan 04 '17 at 14:01
If task is really that simple `print("foo"+k)` will work too. — Yevhen Kuzmovych, Jan 04 '17 at 14:02
Or you can use a dict https://docs.python.org/2/tutorial/datastructures.html#dictionaries — Vitalii Strimbanu, Jan 04 '17 at 14:02
if you use `input()` instead of `raw_input()` , then the user may enter the variable name as input — Sarath Sadasivan Pillai, Jan 04 '17 at 14:08

Patrick Haugh · Answer 1 · 2017-01-04T14:04:03.707

2

Keep the values in a list

l = ['foo1', 'foo2', 'foo3']

Then you can access them by index

print l[0]

outputs

foo1

edited Jan 04 '17 at 14:04

answered Jan 04 '17 at 14:01

Patrick Haugh

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@FrédéricHamidi Absolutely correct. I'll fix my explanation – Patrick Haugh Jan 04 '17 at 14:03

score 0 · Answer 2 · answered Jan 04 '17 at 14:05

0

I recommend using a dict:

{1: 'foo1', 2: 'foo2', ...}[k]

However if you want to use a separate variable for each value then you can use locals() or globals():

locals()['p%d' % k]

(supposing type(k) == int is True)

answered Jan 04 '17 at 14:05

a_guest

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score 0 · Answer 3 · answered Jan 04 '17 at 14:07

lst = [ "foo1", "foo2","foo3","foo4","foo5","foo6","foo7"] #save them as list

userinput = raw_input("Enter value:") #take input from user

print(lst[userinput]) #now the number from user will be the index
# to access your said object

Lets say i inputted 3 then result i get:

foo4

How to refer to variable based on a number in Python?

3 Answers3