CODEWITHSUNDEEP
pythongeneratoryield
junsuzuki
junsuzuki

Reputation: 140

How to check if a yield has been triggered within a method?

In the below method, if a certain condition is met, I'm using yield to return a generator. Within that same method, I'd like to check if the yield has already been triggered (thus the generator populated).

I've read that next(generator) is the common way to check if a generator is empty. But I don't see how I could apply that in this situation where the check has to happened within the method itself.

Here's the snippet :

def my_method(my_list: list) -> List[Iterable]:

    for el in my_list:

        if el == "foo": 
            yield el        

        if <yield_has_been_triggered> and el == "bar":
            break

My current non-elegant solution is :

def my_method(my_list: list) -> List[Iterable]:

    check = False

    for el in my_list:

        if el == "foo":
            check = True
            yield el            

        if check and el == "bar":       
            break

Is there a solution to get this <yield_has_been_triggered> information ?

Upvotes: 1

Views: 143

Answers (1)

michjnich
michjnich

Reputation: 3385

I think you'd probably look at doing that where you actually called the generator tbh:

called = False
for item in my_method(<list>);
    if called and item == "bar": 
        break
    called = True

    ...

But otherwise, pretty much how you've done it I think.

In [3]: def myfunc():
   ...:     _called = False
   ...:     for i in range(10):
   ...:         if _called and i == 5:
   ...:             break
   ...:         _called = True
   ...:         yield i
   ...:

In [4]: for i in myfunc():
   ...:     print(i)
   ...:
0
1
2
3
4

Upvotes: 1

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