python: How do I assign values to letters?

Question

I want to assign a value to each letter in the alphabet, so that a -> 1, b -> 2, c -> 3, ... z -> 26. Something like a function which returns the value of the letter, for example:

value('a') = 1

value('b') = 2

etc...

How would I go about doing this in python?

Answer 1

You want a native python dictionary.

(and you probably also want your values to start from"0" not from "1" , so you can void adding a +1 on all your mappings, as bellow)

Build one with this:

import string
values = dict()
for index, letter in enumerate(string.ascii_lowercase):
   values[letter] = index + 1

This give syou things like:

print values["a"]
-> 1

Of course, you probably could use the "ord" built-in function and skip this dictionary altogether, as in the other answers:

print ord("c") - (ord("a")) + 1

Or in python 3.x or 2.7, you can create the dicionary in a single pass with a dict generator expression:

values = {chr(i): i + 1 for i in range(ord("a"), ord("a") + 26)}