place a 0 in front of numbers in a list if they are less than ten (in python)

Question

Write a Python program that will ask the user to enter a string of lower-case characters and then print its corresponding two-digit code. For example, if the input is "home", the output should be "08151305".

Currently I have my code working to make a list of all the number, but I cannot get it to add a 0 in front of the single digit numbers.

def word ():
    output = []
    input = raw_input("please enter a string of lowercase characters: ")
    for character in input:
        number = ord(character) - 96
        output.append(number)
    print output

This is the output I get:

word()
please enter a string of lowercase characters: abcdefghijklmnopqrstuvwxyz
[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26]

I think I may need to change the list to a string or to integers to do this but I am not sure how to do that.

Answer 1

output.append("%02d" % number) should do it. This uses Python string formatting operations to do left zero padding.

Answer 2

Or, use the built in function designed to do this - zfill():

def word ():
    # could just use a str, no need for a list:
    output = ""
    input = raw_input("please enter a string of lowercase characters: ").strip()
    for character in input:
        number = ord(character) - 96
        # and just append the character code to the output string:
        output += str(number).zfill(2)
    # print output
    return output


print word()
please enter a string of lowercase characters: home
08151305