Code Golf: Numeric equivalent of an Excel column name

Answer 1

MATLAB: 24 characters

polyval(input('')-64,26)

Usage:

>> polyval(input('')-64,26)
(after pressing enter) 'WTF'

ans =

       16074

---

Note: You can get it down to 16 characters if you pre-store the string in x, but I kind of thought it was cheating:

>> x = 'WTF'

x =

WTF

>> polyval(x-64,26)

ans =

       16074

Answer 2

C#, 148 chars

using System;class P{static void Main(string[]a){var r=0d;int j=0,i=a[0].
Length;while(i-->0)r+=(a[0][i]-64)*Math.Pow(26,j++);Console.WriteLine(r);}}

Ungolfed:

using System;
class P
{
    static void Main(string[] a)
    {
        var r = 0d;
        int j = 0, i = a[0].Length;
        while (i-- > 0)
            r += (a[0][i] - 64) * Math.Pow(26, j++);

        Console.WriteLine(r);
    }
}

Answer 3

PHP - 73 Chars

$n=$argv[1];$s=$i=0;while($i<strlen($n))$s=$s*26+ord($n[$i++])-64;echo$s;

Usage:

php -r '$n=$argv[1];$s=$i=0;while($i<strlen($n))$s=$s*26+ord($n[$i++])-64;echo$s;' AA

> 27

Answer 4

J, 17 12 10 characters

26#.64-~av

Example:

26#.64-~av  'WTF'
16074

Explanation:

• J parses from right to left.
• av returns a list of the ascii indexes of each of the characters in its argument, so for example av'ABC' returns 65 66 67.
• Then we subtract 64 from each element of that list with the verb 64-~.
• Then we convert the list to base 26 using the #. verb.

Answer 5

Perl, 34 characters

map$\=26*$\-64+ord,pop=~/./g;print

Thanks to mobrule for several suggestions.

Answer 6

Clojure:

user> (reduce #(+ (* 26 %1) %2) (map #(- (int %) 64) "AD"))
30
user> (reduce #(+ (* 26 %1) %2) (map #(- (int %) 64) "ROFL"))
326676

51 characters, plus the number of characters in the input string.