Python: using variables declared inside if statement

Question

for case in log:
    for event in case:
        if event in process_model:
            index = process_model.index(event)
        else: print(event, index)

---------- output-----------
NameError: name 'index' is not defined

I still need to use index

I don't understand. What would index be in the case that if event in process_model is False? You can give it a default value before if event in process_model but I'm not sure how that fits with "I still need to use index" — roganjosh
– roganjosh, Commented Apr 8, 2018 at 15:22
I need to use the value of index when the event not in process_model . The problem is handling if-statement scop. – — Ahmad
– Ahmad, Commented Apr 9, 2018 at 1:40

Jacques de Hooge · Accepted Answer · 2018-04-08 15:30:23Z

1

Is this what you're looking for?

for case in log:
    for event in case:
        if event in process_model:
            index = process_model.index(event)
        else:
            index = None
        print(event, index)

Or (if case has a __repr__ method and you want to be well informed):

for case in log:
    for event in case:
        if event in process_model:
            index = process_model.index(event)
        else:
            index = None
        print(case, event, index)

edited Apr 8, 2018 at 15:30

answered Apr 8, 2018 at 15:25

Jacques de Hooge

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2 Comments

Ahmad Over a year ago

I need the value of index when the event not in process_model . The problem is handling if-statement scop.

Jacques de Hooge Over a year ago

If event isn't in process_model, index won't have a value, since index indicates the location of event in process_model, which it then doesn't have. That's why it's assigned None. It's like asking for the house number of a house that isn't in a street. It simply doesn't have one. Probably you know what you want, but unfortunately I do not understand what exactly it is...

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