How to union a list of string designing assets and an Asset selection as an asset selection for define_asset_job parameter

To union a list of strings designating assets with an

AssetSelection

object for use in the

selection

parameter of

define_asset_job

, you can use the union operator

|

. The list of strings can be converted into an

AssetSelection

using the

.assets()

method, and then combined with another

AssetSelection

object. Here's an example based on the documentation:

python from dagster import define_asset_job, AssetSelection  # Assuming you have a list of asset keys as strings asset_keys_list = ["asset1", "asset2"]  # Convert the list of strings to an AssetSelection asset_selection_from_list = AssetSelection.assets(*asset_keys_list)  # Assuming you have another AssetSelection object another_asset_selection = AssetSelection.assets("asset3")  # Union the two AssetSelections combined_selection = asset_selection_from_list | another_asset_selection  # Define the job with the combined AssetSelection job = define_asset_job("my_union_job", selection=combined_selection)

In this example,

asset_selection_from_list

is created from a list of asset key strings, and

another_asset_selection

is another

AssetSelection

object. The

|

operator is used to create a union of these two selections, which is then passed to

define_asset_job

as the

selection

parameter. Remember that the

AssetSelection.assets()

method can take multiple asset keys as arguments, and the

|

operator is used to perform the union operation as described in the documentation.

@Scout his code doesn't work

asset_selection_from_list = AssetSelection.assets(*asset_keys_list)

I get this error :

AttributeError: 'list' object has no attribute 'keys'@Scout

I apologize for the confusion. The

AssetSelection.assets()

method expects

AssetKey

objects or strings that represent asset keys, not a list. If you are providing a list of strings, you should ensure that each string in the list is passed as a separate argument to the method. Here's how you can correctly create an

AssetSelection

from a list of strings:

python from dagster import define_asset_job, AssetSelection, AssetKey  # Assuming you have a list of asset keys as strings asset_keys_list = ["asset1", "asset2"]  # Convert the list of strings to an AssetSelection by unpacking the list asset_selection_from_list = AssetSelection.keys(*[AssetKey(key) for key in asset_keys_list])  # Assuming you have another AssetSelection object another_asset_selection = AssetSelection.keys(AssetKey("asset3"))  # Union the two AssetSelections combined_selection = asset_selection_from_list | another_asset_selection  # Define the job with the combined AssetSelection job = define_asset_job("my_union_job", selection=combined_selection)

In this corrected example, we first convert each string in

asset_keys_list

to an

AssetKey

object within a list comprehension. Then we unpack this list of

AssetKey

objects into the

AssetSelection.keys()

method. This should resolve the

AttributeError

you encountered. Please try this corrected approach, and if you encounter any further issues, feel free to ask for additional assistance.