sonder_keypad

keypress.py

num2letter = {"2":"abc", "3":"def", "4":"ghi", "5":"jkl", "6":"mno", 
                "7":"pqrs", "8":"tuv", "9":"wxyz"}


def keys2letters(key_presses):
  results = [x for x in num2letter[key_presses[0]]]
  if len(key_presses) <= 1:
    return(results)
  else:
    for x in key_presses[1:]:
      new_list = [x for x in num2letter[x]]
      results = [i+j for i in results for j in new_list]
    return(results)


# test cases
keys2letters('2')

keys2letters('23')

keys2letters('2345')

keys2letters('222')