```
class Solution(object):
def letterCombinations(self, digits):
"""
:type digits: str
:rtype: List[str]
"""
if not len(digits):
return []
phones = {"1":"" , "2":"abc" , "3":"def" , "4":"ghi" , "5":"jkl" , "6":"mno" , "7":"pqrs" , "8":"tuv" , "9":"wxyz"}
results = []
results.append("")
if not digits.isdigit():
return results
for digit in digits:
if digit == "1":
continue
word = phones[digit]
temp = []
for alphabet in word:
for result in results:
temp.append(result+alphabet)
results = temp
return results
```