Project: Compute a function value as a new field

class txf.Project(source, inputs, output, function)

The Project transform computes (projects) a new field using an arbitrary function of zero or more input fields.

source: Transform

The input pipeline (required).

inputs: tuple(str) or str

The fields to combine. They will not be dropped from the output. Note that nullary functions are supported.

output: str

The field containing the computed result.

function: callable

A callable implementing the function. It will be given the values of inputs as positional arguments in the given order.

Usage

Project(p, 'Number', 'Square', lambda x: x*x)
Project(p, () 'Roll', rand.randint(1,6))