Is

flatten

expected to work on a

dict

?

from prefect import Flow, task, context, flatten

@task
def A():
    return {i: list(range(i)) for i in range(3)}

@task
def B(y):
    logger = context.get("logger")
    <http://logger.info|logger.info>(y)


with Flow('flat map') as f:
    a = A()  # {0: [], 1: [0], 2: [0,1]}
    b = B.map(flatten(a))

if __name__ == "__main__":
    f.run()

I'm getting an unexpected error:

ERROR - prefect.flat map | Unexpected error occured in FlowRunner: KeyError(3)

that doesn't seem like it would do what flatten is supposed to do?

I might be missing something. I'm trying to map over all key-value pairs in the dict.

then i don't see that you need to "flatten" the dict, just return your list(dict.items())

Steve is right. Flatten is to bump nested lists into a one-level list

Sorry, my own example didn't do what I wanted. 🤦‍♂️ This is what I'm looking for:

@task
def flatten_dict(d):
    return [(k, v) for k, v_list in d.items() for v in v_list]

Ahh, Are you good now?

Yeah, just wanted to confirm that

flatten

doesn't cover this.

Yep that’s right