Concat

Concat vertically appends upstream tables. It is useful for collecting rows from alternative branches that produce compatible result columns.

The tool has no inputs. It returns the union of columns; missing values are represented by pandas as nulls. If row indexes collide, the result is reset to a dense integer index to preserve lineage without duplicate index ambiguity.

Use Concat for stacking equivalent measurements, not for joining different measurements for the same objects.

Dependencies and Core Libraries

BioImageFlow DataFrameTool merge APIs and pandas.

Assumptions

Upstream tables describe the same kind of rows or can tolerate missing columns after concatenation.

Minimal Example

from bioimageflow_common_tools import Concat

all_rows = Concat()(batch_a, batch_b, name="all_rows")

Expected Results

Rows from every upstream table are appended vertically.

Failure Modes

Column mismatches produce missing values; duplicate indexes are reset.