replaceLast method

String replaceLast(Pattern from, String replace, [ int startIndex = 0 ])

Replaces the last occurrence of from at or after startIndex with replace.

• A String pattern's last occurrence is the one lastIndexOf finds, even when it overlaps an earlier one: 'aaa'.replaceLast('aa', 'X') is 'aX'.
• Any other Pattern (e.g. a RegExp) replaces the last of its non-overlapping matches, the same matches allMatches and replaceAll use.

Throws RangeError if startIndex is outside 0..length.

See: replaceFirst.

Implementation

String replaceLast(Pattern from, String replace, [int startIndex = 0]) {
  RangeError.checkValueInInterval(startIndex, 0, length, 'startIndex');
  final int start;
  final int end;
  if (from is String) {
    start = lastIndexOf(from);
    if (start < startIndex) return this; // Also covers "not found" (-1).
    end = start + from.length;
  } else {
    final match = from.allMatches(this, startIndex).lastOrNull;
    if (match == null) return this;
    start = match.start;
    end = match.end;
  }
  return substring(0, start) + replace + substring(end);
}