Wolfram Language & System 10.3 (2015)|Legacy Documentation
gives an association whose keys are the distinct letters in string, and whose values give the number of times those letters appear in string.
gives counts of the distinct n-grams consisting of runs of n letters in string.
allows the characters to appear in n-grams, in addition to ordinary letters.
- LetterCounts[string,n] considers n-grams that start at every position in string and includes them in its counts if they contain only letters.
- LetterCounts effectively uses LetterQ to determine whether to consider a character to be a letter.
- LetterCounts has the option IgnoreCase. With the setting IgnoreCase->True, letters are in effect all converted to lower case before being counted.