countLetters method

int countLetters(String target)

To count the occurrences of the letters sequence in a text and check for consecutive occurrences of target letters Here's

an Example:

==================================================================>

String longText = "This is an example text with ab letters and ab words. It also contains abbreviations like abc and abcd. The rabbit jumped over the ab fence.";

int count = longText.countLetters("ab");

print("The sequence 'ab' appears $count times in the text.");

==================================================================>

Implementation

int countLetters(String target) {
  final RegExp targetRegExp = RegExp(target);
  return targetRegExp.allMatches(this).length;
}