lag<T> function

T? lag<T>(
  1. List<T> values,
  2. int index,
  3. int offset
)

Lag: value at index i - offset; null if out of range. Audited: 2026-06-12 11:26 EDT

Implementation

T? lag<T>(List<T> values, int index, int offset) {
  final int j = index - offset;
  return j >= 0 && j < values.length ? values[j] : null;
}