Join / Array Layer
Combine elements from fixed-length string arrays into a single string using a specified separator. Similar to Python's str.join() or R's paste(collapse=).
Example transformation (arrays of length 3):
With separator=', ':
| arrays | joined |
|---|---|
| [red, blue, green] | red, blue, green |
| [x, y, z] | x, y, z |
| [tag1, null, tag3] | tag1, tag3 |
| [null, null, null] | null |
Common applications:
- Combining tags or labels
- Formatting comma-separated lists
- Creating delimited text
- Building display strings
Note: Only works with fixed-length string arrays. All arrays must have the same length. Other array types are not supported.
Select
columnThe fixed-length string array column to join. All arrays must have same length:
- Valid: [red, blue, green]
- Valid: [tag1, tag2, tag3]
- Valid: [2024, 01, 31] Not supported: arrays of numbers, booleans, or other types
Separator
oneofFixed
stringString to insert between array elements. Common separators:
- ', ' for readable lists
- ',' for CSV format
- '|' for pipe-separated values
- ' ' for space-separated words
- '; ' for semicolon separation
SelectSep
columnThe column containing separators
IgnoreNulls
boolControl null value handling:
- true (default): Skip null values ([tag1, null, tag3] → 'tag1, tag3')
- false: Return null if array contains any null values: ([tag1, null, tag3] → null) ([a, b, c] → 'a, b, c')
AsColumn
nameName for the new column. If not provided, the system generates a unique name. If AsColumn matches an existing column, the existing column is replaced. The name should follow valid column naming conventions.