Create new column in Orange using Python Scripting Widget

Question

This is a fairly basic question. How do you create a new column in Orange - based upon an existing column?

For example:

NewCol = 2 * ExistingColumn

or

NewCol = len(ExistingColumn)

I would like to use the Python Script Widget - not the feature widget.

Answer 1

You'd think it would be basic. So far I'm not finding it to be so. Here's one example that worked for me. I'm sure it can be much simpler.:

from Orange.data import ContinuousVariable, DiscreteVariable, Domain

out_data = in_data.copy()
var1 = ContinuousVariable("NewCol")
domain = out_data.domain
new_domain = Domain(attributes=domain.attributes + (var1,), metas=domain.metas, class_vars=domain.class_vars)
out_data = out_data.transform(new_domain)

i2 = out_data.domain.index(out_data.domain["NewCol"])
i1 = out_data.domain.index(out_data.domain["ExistingColumn"])
out_data.X[:, i2] = out_data.X[:,i1] * 2