local variable 'juveniles' referenced before assignment

Chris Angelico rosuav at gmail.com
Wed Jan 13 08:05:15 EST 2016


On Wed, Jan 13, 2016 at 11:54 PM, Alan Robinson
<arobinson at lordlawson.org.uk> wrote:
> On Wednesday, 13 January 2016 12:32:51 UTC, Chris Angelico  wrote:
>> On Wed, Jan 13, 2016 at 11:23 PM, Alan Robinson
>> <arobinson at lordlawson.org.uk> wrote:
>> > def menu():
>> >     option = int(input("Please select an option: \n 1: Set Generation 0 Values \n 2: View Generation 0 Values \n 3: Run Model \n 4: Print values"))
>> >
>> >     if option == 1:
>> >         juveniles,adults,seniles = setGen()
>> >     elif option == 2:
>> >         displayGen()
>> >     elif option == 3:
>> >         runModel(juveniles,adults,seniles)
>> >     elif option == 4:
>> >         print(juveniles,adults,seniles)
>> >     menu()
>> >
>>
>> This is a classic use of recursion instead of iteration. When you call
>> menu() again, you're creating a completely new 'slot' for the new
>> function; it has its own set of names. Assigning to names in one call
>> of menu() has no effect on any other call.
>>
>> Instead, look into the way a while loop works. You'll find that your
>> code is simpler and clearer, plus your variables will stay set.
>>
>> ChrisA
> thanks I need the menu to run again not sure how to do that though

Not quite. You don't want the menu to run again; you want it to
continue to run. Look up the 'while' loop and what it does.

ChrisA



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