Bring your towel and join one of the fastest growing data communities. Welcome to our second-generation open source orchestration platform, a completely rethought approach to dataflow automation.

Prefect Community

Is there a nature way to work with Parameters? e.g the example below will throw an exception because for_date has type Parameter
```with Flow("Demo") as flow:
    for_date = Parameter('for_date', required=True, default='20200101')
    for_date_str = dt.datetime.strptime(for_date, "%Y%m%d")```

I think what I’d like to ask is how to extract the value of a parameter in order to use it somewhere

Hi <@U01UTT5PGD9>! I think the issue here is that `for_date` is a deferred execution that is population at runtime while `for_date_str` happens at run time. You would need to create a helper task to perform that operation and then return it so that the execution gets deferred as well

```@task
def string_to_time(for_date):
    return dt.datetime.strptime(for_date, "%Y%m%d")

with Flow("Demo") as flow:
    for_date = Parameter('for_date', required=True, default='20200101')
    for_date_str = string_to_time(for_date)```

ha, that’s what I am doing, sound to be the `nature` way

<@U01QEJ9PP53> Most times, in operation I'm querying for a date range of 24-48 hours.  However, when I'm launching a new flow, I tend to back date or play around with the date ranges to make sure the flow is robust.

Is there a way to use Parameters to manually set the parameters while the default is dynamically set?

When I tried to set `Parameter('end_date', default=date().today().strptime(...))` the default date is static to when I deployed the flow.

Hi <@U018TAB16PR>, maybe you can try using the <https://docs.prefect.io/api/latest/utilities/context.html#context|context> so it gets populated at runtime? prefect.context.today, and then maybe pass this to a task to format it the way you need?

Otherwise you may need to do this:
```import pendulum
date = Parameter(name="date", default="yesterday")
@task
def generate_date(date_parameter):
    if date_parameter == 'yesterday'
        return pendulum.now().subtract(days=1)
    return pendulum.parse(date_parameter)```

Oooh nice, I like that.  Never played around with any of these utilities actually.  Going to dive in thanks!