withNumericColumnFromFormula method

DataFrame withNumericColumnFromFormula({
  1. required String name,
  2. required String formula,
})

A new data frame with a column calculated from a formula.

Example:

print(sepals.withHead(5));
print(sepals.withHead(5).withNumericColumnFromFormula(
  name: "geom_mean",
  formula: "sqrt(sepal_width * sepal_length)",
));


.--.------------.-----------.
|id|sepal_length|sepal_width|
:--+------------+-----------:
|3 |4.7         |3.2        |
|4 |4.6         |3.1        |
|5 |5.0         |3.6        |
|6 |5.4         |3.9        |
|53|6.9         |3.1        |
'--'------------'-----------'

.--.------------.-----------.------------------.
|id|sepal_length|sepal_width|geom_mean         |
:--+------------+-----------+------------------:
|3 |4.7         |3.2        |3.8781438859330635|
|4 |4.6         |3.1        |3.776241517699841 |
|5 |5.0         |3.6        |4.242640687119285 |
|6 |5.4         |3.9        |4.589117562233507 |
|53|6.9         |3.1        |4.624932431938871 |
'--'------------'-----------'------------------'

Implementation

DataFrame withNumericColumnFromFormula({
  required String name,
  required String formula,
}) {
  if (!_columnNameOkay(name)) {
    throw PackhorseError.badColumnName(name);
  }
  return copy..numericColumns[name] = NumericColumn(_formulaResults(formula));
}