Make the Mexican Wave

Question

In as few bytes as possible, write a program or function that outputs the following:

Abcdefghijklmnopqrstuvwxyz
aBcdefghijklmnopqrstuvwxyz
abCdefghijklmnopqrstuvwxyz
abcDefghijklmnopqrstuvwxyz
abcdEfghijklmnopqrstuvwxyz
abcdeFghijklmnopqrstuvwxyz
abcdefGhijklmnopqrstuvwxyz
abcdefgHijklmnopqrstuvwxyz
abcdefghIjklmnopqrstuvwxyz
abcdefghiJklmnopqrstuvwxyz
abcdefghijKlmnopqrstuvwxyz
abcdefghijkLmnopqrstuvwxyz
abcdefghijklMnopqrstuvwxyz
abcdefghijklmNopqrstuvwxyz
abcdefghijklmnOpqrstuvwxyz
abcdefghijklmnoPqrstuvwxyz
abcdefghijklmnopQrstuvwxyz
abcdefghijklmnopqRstuvwxyz
abcdefghijklmnopqrStuvwxyz
abcdefghijklmnopqrsTuvwxyz
abcdefghijklmnopqrstUvwxyz
abcdefghijklmnopqrstuVwxyz
abcdefghijklmnopqrstuvWxyz
abcdefghijklmnopqrstuvwXyz
abcdefghijklmnopqrstuvwxYz
abcdefghijklmnopqrstuvwxyZ
abcdefghijklmnopqrstuvwxYz
abcdefghijklmnopqrstuvwXyz
abcdefghijklmnopqrstuvWxyz
abcdefghijklmnopqrstuVwxyz
abcdefghijklmnopqrstUvwxyz
abcdefghijklmnopqrsTuvwxyz
abcdefghijklmnopqrStuvwxyz
abcdefghijklmnopqRstuvwxyz
abcdefghijklmnopQrstuvwxyz
abcdefghijklmnoPqrstuvwxyz
abcdefghijklmnOpqrstuvwxyz
abcdefghijklmNopqrstuvwxyz
abcdefghijklMnopqrstuvwxyz
abcdefghijkLmnopqrstuvwxyz
abcdefghijKlmnopqrstuvwxyz
abcdefghiJklmnopqrstuvwxyz
abcdefghIjklmnopqrstuvwxyz
abcdefgHijklmnopqrstuvwxyz
abcdefGhijklmnopqrstuvwxyz
abcdeFghijklmnopqrstuvwxyz
abcdEfghijklmnopqrstuvwxyz
abcDefghijklmnopqrstuvwxyz
abCdefghijklmnopqrstuvwxyz
aBcdefghijklmnopqrstuvwxyz
Abcdefghijklmnopqrstuvwxyz

A trailing newline is permitted. You can find a reference ungolfed Python implementation here.

Answer 1

Pyth, 12 bytes

V+Gt_GXGNrN1

Demonstration.

In Pyth, G is the lowercase alphabet. +Gt_G is abcdefghijklmnopqrstuvwxyzyxwvutsrqponmlkjihgfedcba, the character that needs to be uppercased in each row.

V sets up a for loop over this string, with N as the loop variable.

In the body, XGNrN1 is a string translation function. X translates G, the alphabet, replacing N with rN1, the uppercase version of N. r ... 1 is the uppercase function. This gives the desired output.

Answer 2

C,73

Sometimes the simplest approach is best: print every character one by one. this beats a lot of languages it really shouldn't.

i;f(){for(i=1377;i--;)putchar(i%27?123-i%27-32*!(i/702?i%28-4:i%26):10);}

explanation

i;f(){
   for(i=1377;i--;)
   putchar(i%27?                 //if I not divisible by 27
     123-i%27-                   //  print lowercase letter from ASCII 122 downards
       32*!(i/702?i%28-4:i%26)   //  subtract 32 to make it uppercase where necessary: above i=702, use i%28-4, below it use i%26
     :10);                       //if I divisible by 27 print a newline (10)
}

Answer 3

Python 2, 69 bytes

i=25
exec"L=range(97,123);L[~abs(i)]^=32;i-=1;print bytearray(L);"*51

Nice and simple, I think.

Answer 4

Brainfuck (8bit), 231 bytes

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

Ok, so it's never going to be the shortest, but it's the taking part that counts... right?!

Try it here (ensure to tick 'Dynamic memory')

Answer 5

MS-DOS Binary, 61

This code does not have to be compiled, it will run in MS-DOS if you write it into a file called wave.com . The code in hex:

ba3d0189d7b91a00b061aa404975fbb00aaab00daab024aa31f6e8130046
83fe1a75f7be1800e807004e75fae80100c389d3802820b409cd21800020
c3

Or, if you prefer something more readable, here is how to produce it using debug.exe (the empty line after the code is important):

debug.exe wave.com
a
mov dx,13d
mov di,dx
mov cx,1a
mov al,61
stosb
inc ax
dec cx
jnz 10a
mov al,a
stosb
mov al,d
stosb
mov al,24
stosb
xor si,si
call 130
inc si
cmp si,1a
jnz 11a
mov si,18
call 130
dec si
jnz 126
call 130
ret
mov bx,dx
sub byte ptr [si+bx],20
mov ah,9
int 21
add byte ptr [si+bx],20
ret

rcx
3e
w
q

Answer 6

Ruby: 71 68 65 63 characters

puts f=(e=*?a..?z).map{|c|(e*"").tr c,c.upcase},f[0,25].reverse

Sample run:

bash-4.3$ ruby -e 'puts f=(e=*?a..?z).map{|c|(e*"").tr c,c.upcase},f[0,25].reverse' | head
Abcdefghijklmnopqrstuvwxyz
aBcdefghijklmnopqrstuvwxyz
abCdefghijklmnopqrstuvwxyz
abcDefghijklmnopqrstuvwxyz
abcdEfghijklmnopqrstuvwxyz
abcdeFghijklmnopqrstuvwxyz
abcdefGhijklmnopqrstuvwxyz
abcdefgHijklmnopqrstuvwxyz
abcdefghIjklmnopqrstuvwxyz
abcdefghiJklmnopqrstuvwxyz

Answer 7

Matlab, 60 58 54 bytes

I=32*eye(26);[ones(51,1)*(97:122) '']-[I;I(25:-1:1,:)])

With thanks to Dennis Jaheruddin for saving me 4 bytes.

Answer 8

SWI-Prolog, 136 bytes

a:-(R=0;R=1),between(1,26,I),(I=1,R=0;I\=1,nl),between(1,26,J),(R=0,L=I;R=1,L is 27-I),(J=L,K is J+64,put(K);J\=L,K is J+96,put(K)),\+!.

Abusing backtracking to loop...

Answer 9

Haskell 100 89 88 bytes

putStr$map toEnum.(\(h,c:t)->h++c-32:t++[10]).(`splitAt`[97..122]).(25-).abs=<<[-25..25]

The lambda helper function \(h,c:t) takes a pair of lists of ascii values and concatenates both, but with the first value of the second list capitalized. The main function splits the lowercase alphabet (given in ascii, 97..122) at every position 0,..,24,25,24,..,0 and calls the lambda in every step. Before printing each value is turned into the corresponding character.

Answer 10

Scala 110 109 characters

val a=('a'to'z').map(c⇒('a'to'z').map(v⇒if(v==c)c.toUpper else v).mkString)
a++a.init.reverse foreach println

Answer 11

Haskell, 70 bytes

mapM putStrLn[[toEnum$x+sum[32|x+abs y/=90]|x<-[65..90]]|y<-[-25..25]]

I revisited this problem 6 years later and saved a bunch of bytes. Character growth!

Try it online!

Haskell, 81 bytes

Counting bytes the way @nimi did; f is an IO action that prints the desired output.

x!y|x==min(50-y)y=65|0<1=97
f=mapM putStrLn[[toEnum$x+x!y|x<-[0..25]]|y<-[0..50]]

Answer 12

SQL (postgreSQL), 107 101

Generate are series from -25 to 25 and use the absolute value to replace characters with their uppercase version. Thanks to manatwork for the tip about the @ operator.

select replace('abcdefghijklmnopqrstuvwxyz',chr(122- @i),chr(90- @i))from generate_series(-25,25)a(i)

Answer 13

Pyth - 18 17 bytes

First pass, probably can be made much shorter. Uses X to substitute and r1 to capitalize.

V+KU26t_KXGNr@GN1

Try it online here.

Answer 14

J, 31 23 bytes

u:|:(97+i.26)-32*=|i:25

8 bytes saved thanks to @Mauris.

Try it online here.

Answer 15

MATLAB - 58 bytes

char(bsxfun(@minus,97:122,32*[eye(25,26);rot90(eye(26))]))

Similar to Luis Mendo's solution, but using the broadcasting abilities of bsxfun.

Taking advantage that in ASCII, the difference between a capital and lower case character is exactly 32 values away from each other, we first generate lower case letters from ASCII codes 97 to 122 which are the ASCII codes from lowercase a to lowercase z respectfully, then create a 51 row matrix that contains the 26 ASCII codes from 97 to 122. Therefore, each row of this matrix contains a numerical sequence of values from 97 to 122. Next, we create another matrix where each i^th row of this matrix contains a 32 in the i^th column. The first 26 rows of this matrix has this pattern, which is essentially the identity matrix multiplied by 32. The function eye creates an identity matrix for you. The last 25 rows of this matrix is the scaled identity matrix rotated 90 degrees.

By taking this custom weighted identity matrix and subtracting this with the first matrix, then converting the resulting ASCII codes into characters, the desired "Mexican Hat" sequence is produced.

Example Run

>> char(bsxfun(@minus,97:122,32*[eye(25,26);rot90(eye(26))]))

ans =

Abcdefghijklmnopqrstuvwxyz
aBcdefghijklmnopqrstuvwxyz
abCdefghijklmnopqrstuvwxyz
abcDefghijklmnopqrstuvwxyz
abcdEfghijklmnopqrstuvwxyz
abcdeFghijklmnopqrstuvwxyz
abcdefGhijklmnopqrstuvwxyz
abcdefgHijklmnopqrstuvwxyz
abcdefghIjklmnopqrstuvwxyz
abcdefghiJklmnopqrstuvwxyz
abcdefghijKlmnopqrstuvwxyz
abcdefghijkLmnopqrstuvwxyz
abcdefghijklMnopqrstuvwxyz
abcdefghijklmNopqrstuvwxyz
abcdefghijklmnOpqrstuvwxyz
abcdefghijklmnoPqrstuvwxyz
abcdefghijklmnopQrstuvwxyz
abcdefghijklmnopqRstuvwxyz
abcdefghijklmnopqrStuvwxyz
abcdefghijklmnopqrsTuvwxyz
abcdefghijklmnopqrstUvwxyz
abcdefghijklmnopqrstuVwxyz
abcdefghijklmnopqrstuvWxyz
abcdefghijklmnopqrstuvwXyz
abcdefghijklmnopqrstuvwxYz
abcdefghijklmnopqrstuvwxyZ
abcdefghijklmnopqrstuvwxYz
abcdefghijklmnopqrstuvwXyz
abcdefghijklmnopqrstuvWxyz
abcdefghijklmnopqrstuVwxyz
abcdefghijklmnopqrstUvwxyz
abcdefghijklmnopqrsTuvwxyz
abcdefghijklmnopqrStuvwxyz
abcdefghijklmnopqRstuvwxyz
abcdefghijklmnopQrstuvwxyz
abcdefghijklmnoPqrstuvwxyz
abcdefghijklmnOpqrstuvwxyz
abcdefghijklmNopqrstuvwxyz
abcdefghijklMnopqrstuvwxyz
abcdefghijkLmnopqrstuvwxyz
abcdefghijKlmnopqrstuvwxyz
abcdefghiJklmnopqrstuvwxyz
abcdefghIjklmnopqrstuvwxyz
abcdefgHijklmnopqrstuvwxyz
abcdefGhijklmnopqrstuvwxyz
abcdeFghijklmnopqrstuvwxyz
abcdEfghijklmnopqrstuvwxyz
abcDefghijklmnopqrstuvwxyz
abCdefghijklmnopqrstuvwxyz
aBcdefghijklmnopqrstuvwxyz
Abcdefghijklmnopqrstuvwxyz

You can also run this example using IDEone's online Octave environment. Octave is essentially MATLAB but free: http://ideone.com/PknMe0

Answer 16

Perl, 51 bytes

50 bytes code + 1 byte command line parameter

@a=a..z,@a[-1-abs]=uc@a[-1-abs],print@a for-25..25

Can be used as follows:

perl -le '@a=a..z,@a[-1-abs]=uc@a[-1-abs],print@a for-25..25'

Or online here (note I had to add ,"\n" to this as I couldn't add the -l arg).

---

Much longer method Before the shortened version above, I tried a different method which ended up being pretty chunky. I've left it below anyway for reference.

86 bytes code + 1 byte command line arg

$_=join"",0,a..z,1;print s/1//r while s/(([A-Z])|0)(\D)|(.)((?2))(1)/\L\2\U\3\4\6\L\5/

First Perl I've ever golfed properly so I imagine there's a lot that can be done with it - please do suggest improvements!

Can be used as followed:

perl -le '$_=join"",0,a..z,1;print s/1//r while s/(([A-Z])|0)(\D)|(.)((?2))(1)/\L\2\U\3\4\6\L\5/'

Or online here (note I had to add ."\n" to this as I couldn't add the -l arg).

Explanation

General approach is to use regex substitution to do all the hard work. We start off with:

0abcdefghijklmnopqrstuvwxyz1

This matches (([A-Z])|0)(\D) and gets replaced with \U\3 (\U changes to uppercase) to give:

Abcdefghijklmnopqrstuvwxyz1

From this point onwards, we continue to match the same regex and replace with \L\2\U\3:

aBcdefghijklmnopqrstuvwxyz1
abCdefghijklmnopqrstuvwxyz1
...
abcdefghijklmnopqrstuvwxyZ1

Now the second alternation of the regex matches, (.)((?2))(1) (which is the same as (.)([A-Z])(1)). We replace with \U\4\6\L\5 to give:

abcdefghijklmnopqrstuvwxY1z

This continues to match and replace until we reach:

A1bcdefghijklmnopqrstuvwxyz

and there are no more regex matches.

At each point in the loop we strip off the '1' and print.

Answer 17

PHP, 87 71 69 bytes

Not the shortest one, but it works as intended.
Thanks to @manatwork for a few tips to reduce it's size by a lot.
And thanks to @Blackhole, the size was reduced by 2 bytes.

for(;$L=range(a,z),$L[25-abs($i++-25)]^=' ',$i<52;)echo join($L).'
';

Not exactly pretty, but works.

Answer 18

PowerShell 3.0, 82 bytes

$(0..25)+$(24..0)|%{$i=$_;[string](@(97..122)|%{[char]@($_,($_-32))[$_-eq$i+97]})}

Answer 19

TIS Node Type T21 Architecture - 216 215 bytes

Watch it in action here! There's a DOWN in that video that I later golfed to ANY, but it's functionally identical.

This language has no concept of strings or characters, so I should point out that I'm using ASCII values, i.e. output begins 97, 66, 67...88, 89, 90, 10, 65, 98...

Here's the code in the format of TIS-100's save data, for the purposes of scoring:

@5
ADD 25
L:MOV 27 ANY
SUB 1
JGZ L
MOV 25 ANY
JRO -1
@6
JRO 2
S:MOV 10 ANY
ADD 65
MOV ACC ANY
SUB 90
JEZ S
ADD 26
@9
MOV 32 ANY
ADD UP
L:MOV 0 ANY
SUB 1
JGZ L
@10
MOV UP ACC
ADD ANY
SUB 42
D:JEZ D
ADD 42
MOV ACC ANY

Explanation

Answer 20

JavaScript ES6, 121 bytes

_=>Array(51).fill('abcdefghijklmnopqrstuvwxyz').map((e,i)=>e.replace(/./g,(f,j)=>j==i|i+j==50?f.toUpperCase():f)).join`
`

This is really long because it makes more sense to hardcode the alphabet than to use the absurdly long String.fromCharCode to generate the characters. Test it out below with the Stack snippet, which uses better-supported ES5 and below.

f=function(){
  return Array(51).fill('abcdefghijklmnopqrstuvwxyz').map(function(e,i){
    return e.replace(/./g,function(f,j){
      return j==i|i+j==50?f.toUpperCase():f
    })
  }).join('\n')
}

// Polyfill for ES6-only fill()
Array.prototype.fill = Array.prototype.fill || function(val){
  for(i=0;i<this.length;i++){
    this[i] = val
  }
  return this
}

document.getElementById('p').innerText=f()

<pre id="p"></pre>

Answer 21

CJam, 23 bytes

51{25-z~'{,97>'[2$+tN}/

Try it online in the CJam interpreter.

How it works

51{                  }/ e# For I from 0 to 50:
   25-                  e#   Compute J := I - 25.
                        e#   This maps [0 ... 50] to [-25 ... 25].
      z                 e#   Compute K := abs(J).
                        e#   This maps [-25 ... 25] to [25 ... 0 ... 25].
       ~                e#   Compute L := ~K = -(K + 1).
                        e#   This maps [25 ... 0 ... 25] to [-26 ... -1 ... -26].
        '{,             e#   Push ['\0' ... 'z'].
           97>          e#   Discard the first 97. Pushes ['a' ... 'z'].
              '[2$+     e#   Add L to '['. Pushes 'A' for -26, 'Z' for -1.
                   t    e#   Set ['a' ... 'z'][L] to '[' + L.
                    N   e#   Push a linefeed.

Answer 22

R, 78 70

M=replicate(26,c(letters,"\n"));diag(M)=LETTERS;cat(M,M[,25:1],sep="")

Improved by @MickyT

Answer 23

Bash: 76 66 characters

printf -va %s {a..z}
for c in {a..z} {y..a};{ echo ${a/$c/${c^}};}

Sample run:

bash-4.3$ printf -va %s {a..z};for c in {a..z} {y..a};{ echo ${a/$c/${c^}};} | head
Abcdefghijklmnopqrstuvwxyz
aBcdefghijklmnopqrstuvwxyz
abCdefghijklmnopqrstuvwxyz
abcDefghijklmnopqrstuvwxyz
abcdEfghijklmnopqrstuvwxyz
abcdeFghijklmnopqrstuvwxyz
abcdefGhijklmnopqrstuvwxyz
abcdefgHijklmnopqrstuvwxyz
abcdefghIjklmnopqrstuvwxyz
abcdefghiJklmnopqrstuvwxyz

Answer 24

Linux Assembly, 289

Unfortunately not competitive with high level languages and probably far from optimal, but pretty straightforward. Run it using nasm -f elf64 -o a.o wave.S; ld -s -o a a.o; ./a (the resulting binary is just 568 bytes big):

section .data
s:db 'abcdefghijklmnopqrstuvwxyz',10
section .text
global _start
_start:
mov esi,0
a:call c
inc esi
cmp esi,26
jne a
mov esi,24
b:call c
dec esi
jnz b
call c
mov eax,1
call d
c:mov ecx,s
sub byte [ecx+esi],32
mov eax,4
mov edx,27
d:mov ebx,1
int 80h
add byte [ecx+esi],32
ret

Answer 25

x86 assembly for DOS, 41 Bytes compiled

Binary:

00000000  b9 e6 ff b3 61 b8 61 02  50 38 d8 75 02 24 df 88
00000010  c2 cd 21 58 40 3c 7b 75  ef b2 0a cd 21 41 79 02
00000020  43 43 4b 80 f9 19 75 dd  c3

Source code, save as "wave.asm", compile with "nasm -f bin -o wave.com wave.asm" and run with "dosbox wave.com"

org 100h 
section .text
start:
mov cx,-26
mov bl,'a'
next_line:
mov ax, 0261h
next_char:
push ax
cmp al,bl
jnz lower_case
and al,255-32
lower_case:
mov dl,al
int 21h
pop ax
inc ax
cmp al,'z'+1
jnz next_char
mov dl,0ah
int 21h
inc cx
jns move_left
inc bx
inc bx
move_left:
dec bx
cmp cl,25
jnz next_line
ret

Answer 26

C#, 140 139 135 132

void f(){int d=1,i=0;var s="abcdefghijklmnopqrstuvwxyz\n";for(;i>=0;i+=d=i==25?-1:d)Console.Write(s.Replace(s[i],(char)(s[i]-32)));}

Expanded

void f()
{
    int d = 1, i =0;
    var s = "abcdefghijklmnopqrstuvwxyz\n";
    for (; i >= 0; i += d = i == 25 ? -1 : d)
        Console.Write(s.Replace(s[i], (char)(s[i] - 32)));
}

Saved 1 byte thanks to @Gunther34567 using a ternary instead of if

Saved 4 bytes then nesting that ternary inside the loop and moving the alphabet to the outside of the loop

Saved 3 bytes combining integer declarations thanks to @eatonphil

Answer 27

awk, 91 bytes

awk 'BEGIN{for(i=0;i<51;i++)for(j=0;j<27;j++)printf("%c",j>25?10:i==j||j==50-i?j+65:j+97)}'

Answer 28

Sed: 135 119 116 111 characters

(109 character code + 1 character command line option + 1 character input.)

s/.*/abcdefghijklmnopqrstuvwxyz/
h;H;G;H;G;H;g;G
s/.{,28}/\u&/gp
s/$/\t/
:;s/(\w+\n?)\t(.*)/\t\2\1/;t
s/.*Z//

Sample run:

bash-4.3$ sed -rf mexican.sed <<< '' | head
Abcdefghijklmnopqrstuvwxyz
aBcdefghijklmnopqrstuvwxyz
abCdefghijklmnopqrstuvwxyz
abcDefghijklmnopqrstuvwxyz
abcdEfghijklmnopqrstuvwxyz
abcdeFghijklmnopqrstuvwxyz
abcdefGhijklmnopqrstuvwxyz
abcdefgHijklmnopqrstuvwxyz
abcdefghIjklmnopqrstuvwxyz
abcdefghiJklmnopqrstuvwxyz

Answer 29

Javascript (ES6), 113 bytes

c=-1;while(c++<50){console.log('abcdefghijklmnopqrstuvwxyz'.replace(/./g,(x,i)=>i==c|i+c==50?x.toUpperCase():x))}

110 bytes

for(c=-1;c++<50;)console.log('abcdefghijklmnopqrstuvwxyz'.replace(/./g,(x,i)=>i==c|i+c==50?x.toUpperCase():x))

102 bytes

Old school is unbeatable unless we'll have range operator/function/generator/whatever in js

for(c=-1;c++<50;){for(s='',i=-1;i++<25;)s+=String.fromCharCode(i+(i==c|i+c==50?65:97));console.log(s)}

100 bytes

Unluckily Math.abs is too long

for(c=51;c--;){for(s='',i=26;i--;)s+=String.fromCharCode(c+i==25|c-i==25?90-i:122-i);console.log(s)}

96 94 bytes

Though I've beeing downvoted without explanation I continue my struggle

for(c=-26;c++<25;){for(s='',i=26;i--;)s+=String.fromCharCode(c*c-i*i?122-i:90-i);console.log(s)}

We can shave off a couple of bytes by rearranging loop instructions:

for(c=-26;c++<25;console.log(s))for(s='',i=26;i--;s+=String.fromCharCode(c*c-i*i?122-i:90-i));

Answer 30

Perl - 95 64 bytes

Takes advantage of the fact \u makes the next character printed an uppercase in Perl.

for$c(0..50){$n=1;print map{++$n==27-abs$c-25?"\u$_":$_}a..z,$/}

Thanks to manatwork for saving 31 bytes and fixing it (my previous code did not work.)