Python：使用在if語句中聲明的變量

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

我仍然需要使用索引

Answer 1

這是您要找的東西嗎？

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

或（如果case具有__repr__方法，並且您希望了解情況）：

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)