Alphabet Checksum

Question

Your task

Given a string of lowercase letters, output the "alphabet checksum" of that string, as a letter.

Example

Let's say we have the string "helloworld". With a = 0, b = 1, c = 2 ... z = 25, we can replace all of the letters with numbers:

h  e  l  l  o  w  o  r  l  d
7  4  11 11 14 22 14 17 11 3

Now, we can sum these:

7+4+11+11+14+22+14+17+11+3 = 114

If we mod this by 26, we get:

114 % 26 = 10

Now, using the same numbering system as before, get the 10th letter, k. This is our answer.

Test cases

Input          Output

helloworld     k
abcdef         p
codegolf       h
stackexchange  e
aaaaa          a

This is code-golf, so shortest code in bytes wins.

\$\begingroup\$ Sandbox \$\endgroup\$
– The Thonnu
Oct 21, 2022 at 17:54 — The Thonnu, Oct 21, 2022 at 17:54

Neil · Accepted Answer · 2022-10-22 00:01:47Z

2

Charcoal, 8 bytes

§βΣＥＳ⌕βι

Try it online! Link is to verbose version of code. Explanation:

    Ｓ       Input string
   Ｅ        Map over characters
       ι    Current character
     ⌕      Find index in
      β     Predefined variable lowercase alphabet
  Σ         Take the sum
§           Cyclically indexed into
 β          Predefined variable lowercase alphabet
            Implicitly print

answered Oct 22, 2022 at 0:01

Neil

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Fatalize · Accepted Answer · 2022-10-22 08:24:36Z

2

Brachylog, 14 bytes

ạ+₇ᵐ+%₂₆+₉₇g~ạ

Try it online!

Explanation

ạ                 String to char codes
 +₇ᵐ              Add 7 to each code (a <-> 97 becomes 104 = 0 (mod 26))
    +             Sum
     %₂₆          Mod 26
        +₉₇       Add 97
           g      Wrap into a list
            ~ạ    Char code to string

answered Oct 22, 2022 at 8:24

Fatalize

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Dominic van Essen · Accepted Answer · 2022-10-22 09:35:01Z

2

BQN, 15 bytes

'a'+26|·+´-⟜'a'

Try it at BQN REPL

'a'+26|·+´-⟜'a'
          -⟜'a'     # subtract 'a' from each letter of input
        +´          # sum
       ·            # (no-op to preserve train syntax)
    26|             # modulo 26
'a'+                # add 'a'

answered Oct 22, 2022 at 9:35

Dominic van Essen

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math scat · Accepted Answer · 2022-10-22 10:03:00Z

2

Vyxal, 9 bytes

øA‹∑₄%›øA

Try it Online!

øA‹∑₄%›øA
øA          Letter to number (1-indexed)
  ‹         Decrement each value in list
   ∑        Sum it up
    ₄%›     Modulo by 26 and increment
       øA   Number to letter

edited Oct 22, 2022 at 10:03

answered Oct 21, 2022 at 18:18

math scat

7,6071 gold badge17 silver badges77 bronze badges

\$\begingroup\$ øA‹∑₄%›øA is shorter \$\endgroup\$
– lyxal
Oct 21, 2022 at 22:42
\$\begingroup\$ @lyxal oh wow I didn't know decrement vectorises by default \$\endgroup\$
– math scat
Oct 22, 2022 at 10:01
\$\begingroup\$ 6 bytes by porting the 05AB1E answer. \$\endgroup\$
– user117404
Mar 25 at 15:57

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FlipTack · Accepted Answer · 2022-10-22 14:19:26Z

Pushy, 7 bytes

L7*SvOq

Try it online!

         The input is implicitly converted into bytecodes on the stack.
L7*      Push the length of the input, times 7.
   S     Push the sum of the stack.
    vO   Send this to the 'output stack'.
      q  Index into the ASCII lowercase alphabet (mod 26) and print the result.

Pushing 7 times the length comes from the fact that a has bytecode 97, and \$ -97 \equiv 7 \ (\text{mod} \, 3) \$. So it's equivalent to subtracting 97 from each bytecode.

Knight Industries · Accepted Answer · 2022-10-23 22:39:56Z

2

JavaScript (V8), 72 bytes

([...s])=>String.fromCharCode(s.map(c=>t+=c.charCodeAt()+7,t=0)|t%26+97)

Try it online!

edited Oct 23, 2022 at 22:39

answered Oct 23, 2022 at 20:00

Knight Industries

1513 bronze badges

\$\begingroup\$ Any idea how to get this working also for inputs of size 1 without additional bytes? \$\endgroup\$
– Knight Industries
Oct 25, 2022 at 21:21

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TwoScoopsofPig · Accepted Answer · 2022-10-24 16:26:15Z

2

PowerShell, 54 bytes

$s.tochararray()|%{$r+=([char]$_)-97};[char]($r%26+97)

Try it online!

answered Oct 24, 2022 at 16:26

TwoScoopsofPig

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Baby_Boy · Accepted Answer · 2022-10-24 18:55:48Z

2

Pip, 16 bytes

zPK$+(A*a-97)%26

Try It Online!

answered Oct 24, 2022 at 18:55

Baby_Boy

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Laikoni · Accepted Answer · 2022-11-01 13:23:03Z

2

Haskell, 43 bytes

f s=['a'..]!!mod(sum[fromEnum c-97|c<-s])26

Try it online!

Same-length alternative:

f s=['a'..]!!mod(sum$do c<-s;1<$['b'..c])26

Try it online!

answered Nov 1, 2022 at 13:23

Laikoni

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Sampersand · Accepted Answer · 2022-11-03 07:19:25Z

2

Knight (v2), 36 bytes

;=sP;=i@O;Ws;=i+~-97iAs=s]sA+97%i 26

Try it online!

I feel like you can golf better but i tried for awhile and gave up

answered Nov 3, 2022 at 7:19

Sampersand

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mousetail · Accepted Answer · 2022-11-10 07:38:04Z

2

><> (Fish), 26 24 bytes

-2 bytes thanks to @Eminga. I didn't want to change the input mode to stack though so I didn't use all the golfing potential. Also I wanted to exit properly and not just error.

0i:0(?v+7+2d*%!
o+"a"~<;

Animated Version

Explanation:

Push 0, the starting value

i:0(?v

Check if the input is negative, if so go down.

+7+2d*%

Add 7+the input to the accumulator, then mod 26

Skip the 0 the second time, since the accumulator is already set

~"a"+o;

(Reversed in the program) Print "a" + the accumulator.

edited Nov 10, 2022 at 7:38

answered Nov 4, 2022 at 14:46

mousetail

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1

\$\begingroup\$ You can save 7 bytes by adding 7 to each char code and summing them before modding by 26. \$\endgroup\$
– Emigna
Nov 9, 2022 at 13:04

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Dominic van Essen · Accepted Answer · 2023-01-15 20:51:39Z

2

R, 44 43 42 bytes

letters[sum(utf8ToInt(scan(,""))+7)%%26+1]

Try it online!

(or 38 bytes as a function in R ≥ 4.1).

edited Jan 15 at 20:51

answered Nov 1, 2022 at 9:40

Dominic van Essen

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GammaFunction · Accepted Answer · 2022-10-21 20:13:17Z

1

Zsh, 41 bytes

a=(+##${(s..)^1}+7)
<<<${(#)$((a%26+97))}

Try it online!

(s..)plit, ^ RC-style expand as +##${1[1]}+7 +##${1[2]}+7 .... Then (#) evaluate the expression as character codes.

answered Oct 21, 2022 at 20:13

GammaFunction

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chunes · Accepted Answer · 2022-10-21 22:06:03Z

1

Wren, 47 bytes

Fn.new{|s|(s.bytes.reduce{|x,y|x+7+y}+7)%26+97}

Try it online!

answered Oct 21, 2022 at 22:06

chunes

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Neil · Accepted Answer · 2022-10-22 00:12:14Z

Retina 0.8.2, 25 bytes

0T1>`l`L
+T`l__L`zlL_`^..

Try it online! Link includes test cases. Explanation:

0T1>`l`L

Uppercase all letters after the first.

+T`l__L`zlL_`^..

While there are at least two letters, repeatedly rotate the first letter backwards and the second letter forwards in the alphabet, however the first letter rotates back from a to z while the second letter drops off when it passes Z, allowing subsequent letters to be processed.

The l and L in the patters expand to the lowercase and uppercase alphabet respectively. The _ in the source pattern is just a placeholder to allow the use of l and L in the destination pattern, while in the destination pattern it indicates that the character is to be deleted.

Aiden Chow · Accepted Answer · 2022-10-22 01:35:28Z

1

Pip, 20 bytes

C(($+(7+A*a))%26+97)

Try It Online!

Probably could be shorter, I feel like there are just way too many parentheses.

answered Oct 22, 2022 at 1:35

Aiden Chow

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\$\begingroup\$ Hint: The preset variable z should be quite useful here. \$\endgroup\$
– DLosc
Oct 22, 2022 at 4:02
\$\begingroup\$ @DLosc I literally tried that and it came out longer, I must be doing something horribly wrong \$\endgroup\$
– Aiden Chow
Oct 22, 2022 at 5:02

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manatwork · Accepted Answer · 2022-10-23 20:32:46Z

1

Gema, 77 characters

?=@set{s;@add{${s;};@add{@char-int{?};7}}}
\Z=@int-char{@add{@mod{$s;26};97}}

(Yepp. Arithmetic operations are a pain in Gema.)

Sample run:

bash-5.1$ echo -n helloworld | gema '?=@set{s;@add{${s;};@add{@char-int{?};7}}};\Z=@int-char{@add{@mod{$s;26};97}}'
k

Try it online!

answered Oct 23, 2022 at 20:32

manatwork

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Kai Burghardt · Accepted Answer · 2022-10-24 20:05:10Z

x86‑64 assembly machine code, 30 B

input

unsigned length of string in 64‑bit register rdi
address of string buffer in 64‑bit register rsi

code listing

 1                 alphabet_checksum:
 2 0000 6A61        push 'a'                    ; push(97)
 3 0002 58          pop rax                     ; pop(rax)
 4 0003 F7E7        mul edi                     ; edx○eax ≔ eax × edi
 5                  
 6 0005 F7D8        neg eax                     ; eax ≔ −eax; CF ≔ eax ≠ 0
 7 0007 7310        jnc .adjust                 ; if ¬CF then goto adjust
 8                 .sum:
 9 0009 0FB64C3EFF  movzx ecx, byte [rsi+rdi-1] ; ecx ≔ (rsi + rdi − 1)↑
10 000E 01C8        add eax, ecx                ; eax ≔ eax + ecx
11 0010 FFCF        dec edi                     ; edi ≔ edi − 1; ZF ≔ edi = 0
12 0012 75F5        jnz .sum                    ; if ¬ZF then goto sum
13                  
14 0014 6A1A        push 26                     ; push(26)
15 0016 5F          pop rdi                     ; pop(rdi)
16 0017 F7F7        div edi                     ; edx ≔ edx○eax mod edi
17                 .adjust:
18 0019 92          xchg eax, edx               ; eax ≔ edx
19 001A 83C061      add eax, 'a'                ; eax ≔ eax + 97
20 001D C3          ret

output

alphabet checksum as ASCII character in 64‑bit register rax

limitations

length of string must be ≤ 44,278,013, else the mul spills into edx, yet the algorithm relies on edx being 0 in the case of a zero-length string

What about multiplying edi with -97? Later use cdq to clean edx, with half but still enough range — l4m2, Jan 15 at 7:31

huanglx · Accepted Answer · 2022-12-14 03:27:48Z

C++ (gcc), 76 73 bytes

-3 thanks to @ceilingcat

I think this is as much golf as you can get without using a completely different method. Other people ~~will probably prove me wrong the moment I hit "Post."~~ have in fact proven me wrong.

#import<ios>
int f(char*s){int t=0;for(;*s;t+=*s++-97);putchar(t%26+97);}

Try it online!

Ungolfed

We used #import<ios> so we can putchar().

int f(char* s) {
    int t = 0;                      // Running total
    for(;*s != 0;t += *s++ - 97);   // Loop through string until we get to null byte, add to running total
    putchar(t % 26 + 97);           // Add 97 to final result and print
}

chunes · Accepted Answer · 2023-01-15 02:50:52Z

1

Arturo, 29 bytes

$[a][+97(sum map a=>[+7])%26]

Try it

answered Jan 15 at 2:50

chunes

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l4m2 · Accepted Answer · 2023-01-15 11:57:01Z

1

brainfuck, 91 bytes

++[++[->+>+<<]>>[--<<+>>]<],[[-[->+<]>]>>>>>>>,]+[<<<<<<<<<<<<<<<<<<<<<<<<<<+<[-----.[>]]>]

Try it online!

++[++[->+>+<<]>>[--<<+>>]<]    Init memory with 1,2,3,...,127
,[[-[->+<]>]>>>>>>>,]          Reading each byte, move right that many steps
+[<<<<<<<<<<<<<<<<<<<<<<<<<<+< Go left 26 and check if empty
[-----.[>]]>]                  If not empty, give shift, output and halt

edited Jan 15 at 11:57

answered Jan 15 at 5:49

l4m2

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Andriy Makukha · Accepted Answer · 2023-01-16 02:51:31Z

1

Dyalog APL v18, 28 bytes*

{a[1+26|+/1-⍨(a←¯1∘⎕C⎕A)⍳⍵]}

Assuming that indices start from one (⎕IO←1).

^{________________

*: APL can be written in its own legacy charset (defined by ⎕AV) instead of Unicode; therefore an APL program that only uses ASCII characters and APL symbols can be scored as 1 char = 1 byte.}

edited Jan 16 at 2:51

answered Jan 16 at 2:44

Andriy Makukha

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Stack Exchange Network

Alphabet Checksum

Your task

Example

Test cases

52 Answers 52

Charcoal, 8 bytes

Brachylog, 14 bytes

Explanation

BQN, 15 bytes

Vyxal, 9 bytes

Pushy, 7 bytes

JavaScript (V8), 72 bytes

PowerShell, 54 bytes

Pip, 16 bytes

Haskell, 43 bytes

Same-length alternative:

Knight (v2), 36 bytes

><> (Fish), 26 24 bytes

Explanation:

R, 44 43 42 bytes

Zsh, 41 bytes

Wren, 47 bytes

Retina 0.8.2, 25 bytes

Pip, 20 bytes

Gema, 77 characters

x86‑64 assembly machine code, 30 B

input

code listing

output

limitations

C++ (gcc), 76 73 bytes

Ungolfed

Arturo, 29 bytes

brainfuck, 91 bytes

Dyalog APL v18, 28 bytes*

Your Answer

Not the answer you're looking for? Browse other questions tagged
code-golf
string
alphabet
or ask your own question.

Hot Network Questions

Alphabet Checksum

Your task

Example

Test cases

52 Answers 52

Charcoal, 8 bytes

Brachylog, 14 bytes

Explanation

BQN, 15 bytes

Vyxal, 9 bytes

Pushy, 7 bytes

JavaScript (V8), 72 bytes

PowerShell, 54 bytes

Pip, 16 bytes

Haskell, 43 bytes

Same-length alternative:

Knight (v2), 36 bytes

><> (Fish), 26 24 bytes

Explanation:

R, 44 43 42 bytes

Zsh, 41 bytes

Wren, 47 bytes

Retina 0.8.2, 25 bytes

Pip, 20 bytes

Gema, 77 characters

x86‑64 assembly machine code, 30 B

input

code listing

output

limitations

C++ (gcc), 76 73 bytes

Ungolfed

Arturo, 29 bytes

brainfuck, 91 bytes

Dyalog APL v18, 28 bytes*

Your Answer

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Not the answer you're looking for? Browse other questions tagged code-golfstringalphabet or ask your own question.

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x86‑64 assembly machine code, 30 B

Not the answer you're looking for? Browse other questions tagged
code-golf
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