Column transformers

[isair]

Support passing an option with transformer functions that'll be applied to values belonging to a specific column. Before data is converted into tensors and tensor operations such as standardisation are applied.

e.g.

const { ... } = loadCsv('data.csv', {
  ...
  labelColumns: ['temperature'],
  ...
  columnTransformers: {
    temperature: (fahrenheit) => (fahrenheit - 32) * 5 / 9,
  },
});