groupingBy<K> method
Group elements by a key.
It creates a Grouping
using the specified keySelector
to extract a
key from each character.
It can then be used with one of its group-and-fold operations.
final words = 'one two three four five six seven eight nine ten';
final frequenciesByFirstChar =
words.groupingBy((value) => value[0]).eachCount();
print('Counting first letters:');
print(frequenciesByFirstChar); // {o=1, t=3, f=2, s=2, e=1, n=1}
Implementation
Grouping<String, K> groupingBy<K>(K Function(String value) keySelector) {
return split('').groupingBy(keySelector);
}