extent<T extends Comparable?> function Summarizing data

(T?, T?) extent<T extends Comparable?>(
  1. Iterable<T> iterable
)

Returns the minimum and maximum values in the iterable.

The minimum and maximum values are determined based on the natural ordering of the values, as defined by the Comparable interface.

This function ignores values that do not satisfy any of the following conditions:

  1. The value is not null.
  2. The value is not a special case like double.nan, which does not satisfy self-equality according to Object.==.

Useful for filtering and ignoring missing data in datasets.

If the iterable is empty or contains no valid values, this function returns (null, null).

Implementation

(T?, T?) extent<T extends Comparable?>(Iterable<T> iterable) {
  T? min, max;
  for (final value in iterable) {
    if (value == null || value != value) continue;
    if (min == null || max == null) {
      min = max = value;
      continue;
    }
    if (min.compareTo(value) > 0) min = value;
    if (max.compareTo(value) < 0) max = value;
  }
  return (min, max);
}