Converting Letters to Pre-Smartphone Numeric Codes

Tomaz Kastrun rolls back the clocks:

What a nightmare was to type a short message on these keypads. So, image writing Hello on this keypad, you had to press: 4433555555666 to get the letters “hello”.

44 = h
33 = e
555 = l
555 = l
666 = o

So creating converter would be great to troll on your friends

This seems like as good a reason as any to create such a function. Click through to see how to do it in R.