### Name: alphabetFrequency
### Title: Function to calculate the frequency of letters in a biological
###   sequence
### Aliases: alphabetFrequency alphabetFrequency,BString-method
###   alphabetFrequency,DNAString-method alphabetFrequency,RNAString-method
###   alphabetFrequency,BStringViews-method alphabetFrequency
### Keywords: category

### ** Examples

  data(yeastSEQCHR1)
  yeast1 <- DNAString(yeastSEQCHR1)
  alphabetFrequency(yeast1)
  alphabetFrequency(yeast1, baseOnly=FALSE)