Add Columns component

This article describes a component in Azure Machine Learning designer.

Use this component to concatenate two datasets. You combine all columns from the two datasets that you specify as inputs to create a single dataset. If you need to concatenate more than two datasets, use several instances of Add Columns.

How to configure Add Columns

1. Add the Add Columns component to your pipeline.

2. Connect the two datasets that you want to concatenate. If you want to combine more than two datasets, you can chain together several combinations of Add Columns.

   • It is possible to combine two columns that have a different number of rows. The output dataset is padded with missing values for each row in the smaller source column.

   • You cannot choose individual columns to add. All the columns from each dataset are concatenated when you use Add Columns. Therefore, if you want to add only a subset of the columns, use Select Columns in Dataset to create a dataset with the columns you want.

3. Submit the pipeline.

Results

After the pipeline has run:

• To see the first rows of the new dataset, right-click the Add Columns component and select Visualize. Or Select the component and switch to the Outputs tab in the right panel, click on the histogram icon in the Port outputs to visualize the result.

The number of columns in the new dataset equals the sum of the columns of both input datasets.

If there are two columns with the same name in the input datasets, a numeric suffix is added to the name of the column. For example, if there are two instances of a column named TargetOutcome, the left column would be renamed TargetOutcome_1 and the right column would be renamed TargetOutcome_2.

Next steps

See the set of components available to Azure Machine Learning.