Code Golf: Numeric equivalent of an Excel column name - excel

Question

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The challenge
The shortest code by character count that will output the numeric equivalent of an Excel column string.
For example, the A column is 1, B is 2, so on and so forth. Once you hit Z, the next column becomes AA, then AB and so on.
Test cases:
A: 1
B: 2
AD: 30
ABC: 731
WTF: 16074
ROFL: 326676
Code count includes input/output (i.e full program).

Answer 1

Excel, 9 chars :)
Use the right tool for the job:
=COLUMN()

Answer 2

Perl, 36 34 33 31 30 17 15 11 characters
$_=()=A..$_
Usage:
$ echo -n WTF | perl -ple '$_=()=A..$_'
16074
Reduced to 17 by using echo -n to avoid a chop call.
Reduced to 15 by using say instead of print.
Reduced to 11 by using -p instead of say.
Explanation:
A is evaluated in string context and A..$_ builds a list starting at "A" and string-incrementing up to the input string. Perl interprets the ++ operator (and thus ..) on strings in an alphabetic context, so for example $_="AZ";$_++;print outputs BA.
=()= (aka "goatse" operator) forces an expression to be evaluated in list context, and returns the number of elements returned by that expression i.e., $scalar = () = <expr> corresponds to #list = <expr>; $scalar = #list.

Answer 3

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 4

Brainf*ck, 81 characters (no whitespace)
,[>>>[->>+++++[-<+++++>]<+<]>[-<+>]<<++++++++[<++++++++>-]<[<->-]<[>>>+<<<-],]>>>
Explanation
,[ // get character input into p[0], enter loop if it isn't null (0)
>>>[->>+++++[-<+++++>]<+<] // take what's in p[3] and multiply by 26, storing it in p[4]
>[-<+>] // copy p[4] back to p[3]
<<++++++++[<++++++++>-]< // store 64 in p[1]
[<->-]< // subtract p[1], which is 64, from the input char to get it's alphabetical index
[>>>+<<<-] // add p[0] to p[3]
,] // get another character and repeat
>>> // move to p[3], where our final result is stored
So you'll notice I didn't actually convert the numerical value to an ascii string for printing. That would likely ruin the fun. But I did the favor of moving the pointer to the cell with the result, so at least it's useful to the machine.
Hey, what do you know, I beat C#!

Answer 5

Ruby 1.8.7, 53 50 46 44 24 17 characters
p ('A'..$_).count
Usage:
$ echo -n ROFL | ruby -n a.rb
326676
$ echo -n WTF | ruby -n a.rb
16074
$ echo -n A | ruby -n a.rb
1

Answer 6

APL
13 characters
Put the value in x:
x←'WTF'
then compute it with:
26⊥(⎕aV⍳x)-65
The only reason J beat me is because of the parentheses. I'm thinking there should be some way to rearrange it to avoid the need for them, but it's been a long day. Ideas?
(Heh, you perl programmers with your 30+ character solutions are so cute!)

Answer 7

Excel (not cheating), 25 chars
Supports up to XFD:
=COLUMN(INDIRECT(A1&"1"))
Installation:
Put the formula in cell A2.
Usage:
Enter the column string in cell A1.
Read the result at cell A2.
54 chars, plus a lot of instructions
Supports ROFL also:
(A2) =MAX(B:B)
(B2) =IFERROR(26*B1+CODE(MID(A$1,ROW()-1,1))-64,0)
Installation:
Clear the whole spreadsheet.
Put the formula (A2) in cell A2.
Put the formula (B2) in cell B2.
Fill formula (B2) to as far down as possible.
Usage:
Enter the column string in cell A1.
Read the result at cell A2.

Answer 8

C# 156 146 118 Chars
using System.Linq;class P{static void Main(string[]a){System.Console.Write(
a[0].Aggregate(0,(t,c)=>(t+c-64)*26)/26);}}
Ungolfed:
using System.Linq;
class P
{
static void Main(string[] a)
{
System.Console.Write(a[0]
.Aggregate(0, (t, c) => (t + c - 64) * 26) / 26);
}
}

Answer 9

Golfscript - 16 chars
[0]\+{31&\26*+}*
$ echo -n WTF | ./golfscript.rb excel.gs
16074
$ echo -n ROFL | ./golfscript.rb excel.gs
326676

Answer 10

Haskell, 50 51 56 chars
main=interact$show.foldl(\x->(26*x-64+).fromEnum)0
Usage:
~:166$ echo -n "ROFL" | ./a.out
326676
~:167$ echo -n "WTF" | ./a.out
16074

Answer 11

Python, 64 49 characters
s=0
for c in raw_input():s=26*s+ord(c)-64
print s
You can also replace raw_input() with input() to reduce the character count by 4, but that then requires the input to contain quotation marks around it.
And here's a subroutine that clocks in at 47 characters:
f=lambda x:len(x)and 26*f(x[:-1])+ord(x[-1])-64

Answer 12

k4 (kdb+), 11 characters
26/:1+.Q.A?
Explanation:
k4 parses left of right
.Q.A is defined within k4 - it is the vector "ABC...XYZ"
? is the find operator - the index of the first match for items in the y arg within the x arg
+1 to offset the index
26/: to convert to base 26
One caveat - this will only work where listed types are passed in:
26/:1+.Q.A? "AD"
30
26/:1+.Q.A? "WTF"
16074
but:
26/:1+.Q.A? ,"A"
1

Answer 13

Powershell, 42 chars
[char[]]$args[($s=0)]|%{$s=$s*26+$_-64};$s

Answer 14

JavaScript 1.8: 66 characters
function a(p)Array.reduce(p,function(t,d)t*26+d.charCodeAt()-64,0)
Javascript 1.8: 72 characters
function a(p)(t=0,p.replace(/./g,function(d)t=t*26+d.charCodeAt()-64),t)
JavaScript 1.6: 83 characters
function a(p){t=0;p.split("").map(function(d){t=t*26+d.charCodeAt(0)-64});return t}
JavaScript: 95 characters
function a(p){r=0;t=1;l=p.length;for(i=0;i<l;i++){r+=(p.charCodeAt(l-1-i)-64)*t;t*=26}return r}
JavaScript: 105 characters
function a(p,i){i=i||0;l=p.length;return p?(p.charCodeAt(l-1)-64)*Math.pow(26,i)+a(p.slice(0,l-1),i+1):0}
Usage:
a("A") // 1
a("B") // 2
a("AD") // 30
a("ABC") // 731
a("WTF") // 16074
a("ROFL") // 326676

Answer 15

Scala, 30 chars
print((0/:args(0))(_*26+_-64))"
Example:
C:\>scala -e "print((0/:args(0))(_*26+_-64))" AD
30

Answer 16

C89, 58 characters
s;main(c){while(c=getchar()+1)s=26*s+c-65;printf("%d",s);}
The input (stdin) must contain only A-Z, no other characters (including newlines) are allowed.

Answer 17

Explanation of Concepts - Excelcification
Nice. I wrote my own version of this with a little more explanation a long time ago at
http://aboutdev.wordpress.com/2009/12/19/excelcification-brain-teaser-code/. Although it's not quite an optimized version!
FYI. The base 26 arithmetic is called hexavigesimal and Excel's maximum column is XFD which converts to 16383 (using 0 as the first cell) which is coincidentally exactly 2^14 cells.
Can anyone guess as to why it is 2^14??

Answer 18

Common Lisp, 103 128 characters
(defun x(s)(reduce(lambda(x y)(+(* 26 x)y))(map 'vector(lambda(b)(-(char-code b)(char-code #\A)-1))s)))

Answer 19

C#, 117 111 chars
No contest compared to the likes of Perl, Ruby and APL but an improvement on the other C#/Java answers given so far.
This uses Horner's rule.
class C{static void Main(string[]a){int t=0;foreach(var c in a[0]){t=(t+c-64)*26;}System.Console.Write(t/26);}}

Answer 20

Perl, 34 characters
map$\=26*$\-64+ord,pop=~/./g;print
Thanks to mobrule for several suggestions.

Answer 21

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 22

Python - 63 chars
>>> f=lambda z: reduce(lambda x,y: 26*x+y, [ord(c)-64 for c in z])
>>> f('ROFL')
326676

Answer 23

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.

Answer 24

C:
int r=0;
while(*c)r=r*26+*c++-64;
String is stored in 'c', value is in 'r'.

Answer 25

Ruby 1.9, 21 characters
p'A'.upto(gets).count
Tests:
$ echo -n A| ruby x.rb
1
$ echo -n WTF| ruby x.rb
16074
$ echo -n ROFL| ruby x.rb
326676

Answer 26

Common Lisp, 86 characters.
(defun z(s)(let((a 0))(map nil(lambda(v)(setf a(+(* 26 a)(digit-char-p v 36)-9)))s)a))

Answer 27

Java: 112 124 characters
class C{public static void main(String[]a){int r=0;for(int b:a[0].getBytes())r=26*r+b-64;System.out.print(r);}}

Answer 28

Common Lisp, 81 characters
(defun y(s)(reduce(lambda(x y)(+(* 26 x)(-(char-code y)64)))s :initial-value 0))
Funny that as a new user I can post my own answer but not comment on someone else's. Oh well, apologies if I'm doing this wrong!

Answer 29

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 30

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