Collect
Overview¶
The Collect Block is used to gather data from a channel and store it in a list. Once the channel closes, the Block outputs the collected items as a list.
The Collect Block listens for events from an InputChannel and appends the incoming data to an internal list (items_state). When the channel sends a close event, the collected data is sent out via the items output.
Description¶
Collects data from a channel and outputs them as a list once the channel closes
Metadata¶
- Category: Function
Configuration Options¶
No configuration options available.
Inputs¶
| Name | Data Type | Description |
|---|---|---|
| item | InputChannel[ItemT] |
Outputs¶
| Name | Data Type | Description |
|---|---|---|
| items | list[ItemT] |
State Variables¶
| Name | Data Type | Description |
|---|---|---|
| items_state | list[ItemT] |
Example(s)¶
Example 1: Collect data from an input channel¶
- Create a
CollectBlock. - Provide an
InputChannelthat sends individual pieces of data. - As the
InputChannelsends data, the Block will collect each item. - When the channel closes, the Block will output the collected list.
Example 2: Gather event-based data¶
- Use the
CollectBlock to accumulate data from an event stream. - For example, during a long-running process, events can be sent via an
InputChannel. - Once the process completes and the channel closes, the Block will output the accumulated data as a list of events.
Error Handling¶
- The
CollectBlock assumes that data will be available on the channel. If no data is received, the output list will be empty. - Make sure the channel is properly closed; otherwise, the Block will not output the collected data.
FAQ¶
What happens if no data is sent before the channel closes?
If no data is received from the channel before it closes, the Collect Block will output an empty list.
Can I use this block to collect data from multiple channels?
The current design of the Collect Block focuses on a single channel. To collect data from multiple channels, you'll need to implement additional logic to manage multiple channels.
What happens if the channel does not send a close event?
The Collect Block only sends the collected data when it detects a close event. If the channel remains open indefinitely, the collected data will not be outputted.