Concat Rows
Concat Rows (Union / Concat) — concatRows
Stack multiple inputs row-wise (no config). This is the variadic node — connect two or more upstream nodes to its input handle and they're concatenated in order.
Use cases
- Combine monthly files into one dataset.
- Append a new batch to an existing one before further cleaning.
What it does
Stacks all connected inputs row-wise in connection order. Column alignment happens by name: inputs with different schemas produce null for missing columns.
Before
| region | amount |
|---|---|
| North | 100 |
| South | 80 |
2 rows · 2 cols
Union / Concat (Input A + Input B stacked)
After
| region | amount |
|---|---|
| North | 100 |
| South | 80 |
| East | 150 |
| West | 90 |
4 rows · 2 cols
The Before pane above shows Input A; the After pane shows the stacked result
after appending Input B (East/150, West/90). Connect as many inputs as you need.
Configuration
This node has no configuration — it stacks whatever inputs are connected.
Generated Python code
df_3 = pd.concat([df_1, df_2], ignore_index=True)
Tips & common mistakes
- Align columns first. Inputs with different column names produce sparse rows (missing columns become null) — use Rename columns / Select columns to match schemas.
- Concat stacks rows; to combine columns on a key use Join.
- Use Remove duplicates afterward if sources overlap.