# How to convert a char array to a number for sorting?

Let’s say I have three words I want to sort:

• hello
• goodbye
• alex

And alphabetically it’d be sorted ascendingly as `["alex", "goodbye", "hello"]`. Is there a way to convert the string (limited to 100 characters)? For example, if I have:

``````['a', 'l', 'e', 'x']
``````

And I use `ord` to get the code for each list-element:

``````[1, 12, 5, 24]
``````

How would I create a number from that, that would also be smaller than, say, `goodbye` ?

### >Solution :

Use:

``````from operator import mul, pow
from itertools import repeat

LIMIT = 100
char_vals = [1, 12, 5, 24]
sum(map(mul, char_vals, map(pow, repeat(27), range(LIMIT, 0, -1))))
``````

Since you’ve bounded the length of the strings, you can think of each word as a base-27 number. 0 represents that the letter doesn’t exist, 1 represents `a`, 2 represents `b`, etc.

Then, the numerical value of each word can be computed using the following polynomial:

``````i_1 * 27**100 + i_2 * 27**99 + ...
``````

where `char_vals = [i_1, i_2, ...]` (i.e. each `i` is the integer value of the corresponding letter).