# replaceRange method

void replaceRange (int start, int end, Iterable<E> newContents)
override

Removes the objects in the range `start` inclusive to `end` exclusive and inserts the contents of `replacement` in its place.

    List<int> list = [1, 2, 3, 4, 5];
    list.replaceRange(1, 4, [6, 7]);
    list.join(', '); // '1, 6, 7, 5'

The provided range, given by `start` and `end`, must be valid. A range from `start` to `end` is valid if `0 <= start <= end <= len`, where `len` is this list's `length`. The range starts at `start` and has length `end - start`. An empty range (with `end == start`) is valid.

This method does not work on fixed-length lists, even when `replacement` has the same number of elements as the replaced range. In that case use setRange instead.

## Implementation

    void replaceRange(int start, int end, Iterable<E> newContents) {
      RangeError.checkValidRange(start, end, this.length);
      if (newContents is! EfficientLengthIterable) {
        newContents = newContents.toList();
      }
      int removeLength = end - start;
      int insertLength = newContents.length;
      if (removeLength >= insertLength) {
        int insertEnd = start + insertLength;
        this.setRange(start, insertEnd, newContents);
        if (removeLength > insertLength) {
          _closeGap(insertEnd, end);
        }
      } else {
        int delta = insertLength - removeLength;
        int newLength = this.length + delta;
        int insertEnd = start + insertLength; // aka. end + delta.
        this.length = newLength;
        this.setRange(insertEnd, newLength, this, end);
        this.setRange(start, insertEnd, newContents);
      }
    }