group package:bytestring

group :: ByteString -> [ByteString]
bytestring Data.ByteString Data.ByteString.Char8
The group function takes a ByteString and returns a list of ByteStrings such that the concatenation of the result is equal to the argument. Moreover, each string in the result contains only equal elements. For example, 
group "Mississippi" = ["M","i","ss","i","ss","i","pp","i"]
It is a special case of groupBy, which allows the programmer to supply their own equality test. It is about 40% faster than groupBy (==)
group :: ByteString -> [ByteString]
bytestring Data.ByteString.Lazy Data.ByteString.Lazy.Char8
The group function takes a ByteString and returns a list of ByteStrings such that the concatenation of the result is equal to the argument. Moreover, each string in the result contains only equal elements. For example, 
group "Mississippi" = ["M","i","ss","i","ss","i","pp","i"]
It is a special case of groupBy, which allows the programmer to supply their own equality test.
groupBy :: (Word8 -> Word8 -> Bool) -> ByteString -> [ByteString]
bytestring Data.ByteString Data.ByteString.Lazy
The groupBy function is the non-overloaded version of group.
groupBy :: (Char -> Char -> Bool) -> ByteString -> [ByteString]
bytestring Data.ByteString.Char8 Data.ByteString.Lazy.Char8
The groupBy function is the non-overloaded version of group.