Toggle Shift Key

Question

Objective

Given an ASCII character, toggle its "shift-ness" on the standard US keyboard (ANSI-INCITS 154-1988 (R1999)), then output it.

Mapping

) ↔️ 0
! ↔️ 1
@ ↔️ 2
# ↔️ 3
$ ↔️ 4
% ↔️ 5
^ ↔️ 6
& ↔️ 7
* ↔️ 8
( ↔️ 9
" ↔️ '
+ ↔️ =
, ↔️ <
- ↔️ _
. ↔️ >
/ ↔️ ?
: ↔️ ;
(Capital Latin letters) ↔️ (Small Latin letters)
[ ↔️ {
\ ↔️ |
] ↔️ }
` ↔️ ~
(ASCII whitespaces and control characters are left intact)

Rule

• Non-ASCII characters fall into don't care situation.

Examples

Given a character 0, output ).
Given a character C, output c.
Given a character (space), output .
Given a character \t (horizontal tab), output \t.
Given a character \a (bell), output \a.

Answer 1

JavaScript (Node.js),  110 ... 97  96 bytes

c=>(s=")0@2^6&7*8(9\"'+=-_:;`~")[s.indexOf(c)^1]||(B=Buffer)([([n]=B(c),n%127>32)<<4+n/64^n])+''

Try it online!

How?

We use a lookup table for these pairs:

) ↔️ 0
@ ↔️ 2
^ ↔️ 6
& ↔️ 7
* ↔️ 8
( ↔️ 9
" ↔️ '
+ ↔️ =
- ↔️ _
: ↔️ ;
` ↔️ ~

For all other characters, we use the following code:

(B = Buffer)([   // generate a buffer from a singleton array:
  (              //
    [n] = B(c),  //   n = ASCII code of the input character
    n % 127 > 32 //   1 if 32 < n < 127, or 0 otherwise
  )              //
  << 4 + n / 64  //   left-shifted by 4 if n < 64, or by 5 otherwise
  ^ n            //   XOR'ed with n
]) + ''          // end of Buffer(); coerce it to a string

which supports these 3 cases:

• If \$32<n<64\$, we XOR the ASCII code with \$16\$, which is what we need for:

  ! ↔️ 1
  # ↔️ 3
  $ ↔️ 4
  % ↔️ 5
  , ↔️ <
  . ↔️ >
  / ↔️ ?
  

• If \$64\le n<127\$, we XOR the ASCII code with \$32\$, which toggles the case of letters and also works for these pairs:

  [ ↔️ {
  \ ↔️ |
  ] ↔️ }
  

• If \$n\le32\$ or \$n=127\$, the character is left unchanged (ASCII code XOR'ed with \$0\$).

Answer 2

Retina 0.8.2, 34 bytes

T`-~A-]d';-?/.+,:"(*&^%$#@!)}-_`Ro

Try it online! Link includes test cases.

Explanation: The T command is Retina's transliteration operation. Among its special characters are:

• `: Delimit the parts of the command
• -: Introduce a range (this suppresses the following special characters so d-o just means defghijklmno)
• _: Delete the matching character
• d: 0-9
• R: Reverse the next range
• o: Take the source string as the range

The trick is therefore to create as many ranges as possible to reduce the length, plus avoiding having the - and _ characters where they would be interpreted as a special character and avoiding the ` at all by including it inside a range. Additionally arranging for the range to transliterate to its reversal allows that to be expressed very cheaply.

Answer 3

x86-16, Genuine IBM PC, 32 31 29 bytes

00000000: b4f0 8ec0 bfe5 e8b3 3ab1 74a0 8200 f2ae  ........:.t.....
00000010: 3acb 7f02 f7db 268a 41ff cd29 c3         :.....&.A..).

Build with xxd -r.

Unassembled listing:

B4 F0       MOV  AH, 0F0H               ; BIOS segment address (F000H)
8E C0       MOV  ES, AX                 ; set ES to BIOS segment for SCASB
BF E8E5     MOV  DI, E8E5H              ; set to LABEL K10 
B3 3A       MOV  BL, 58                 ; size of table 
B1 74       MOV  CL, 58*2               ; size of both tables 
A0 0082     MOV  AL, BYTE PTR DS:[82H]  ; get input char from command line 
F2/ AE      REPNZ SCASB                 ; search BIOS table for char 
3A CB       CMP  CL, BL                 ; found in the lowercase table? 
7F 02       JG   UPPER                  ; if so, convert with uppercase table by adding
F7 DB       NEG  BX                     ; otherwise subtract the offset 
        UPPER: 
26:8A 41 FF MOV  AL, ES:[BX+DI-1]       ; get char from table
CD 29       INT  29H                    ; DOS fast write to console 
C3          RET                         ; return to DOS

Input/Output:

How does it work?

Well, the PC BIOS already contains all of the code and tables necessary for this since it actually handles the conversion of scan codes received from the keyboard to ASCII chars (in real/DOS mode at least). There's no way (that I know of) to actually hook this on just any "PC-compatible" BIOS, however if you know the location of the table in ROM (on the IBM PC it starts at F000:E8E5), you can use that.

On Page A-25 of Appendix A the IBM PC Technical Reference (listing of the entire source code of the PC BIOS) is the disassembly of this table:

Unfortunately, this address will be different on any given PC-clone BIOS and of course, there's no guarantee that it would even be implemented in the same way by anyone else. Thus, this submission is guaranteed to run only on a Genuine IBM PC. Go Big Blue!

Answer 4

Bash + core utilities, ^{58 \$\cdots\$ 51} 49 bytes

Added 47 50 bytes to fix a bug kindly pointed out by Giuseppe.
Saved 8 bytes thanks to Value Ink!!!
Saved 2 bytes thanks to Mitchell Spector!!!

a='"A-]`=<_>?)!@#$%^&*(;'
b=\'a-~+-:
tr $a$b $b$a

Try it online!

Answer 5

Python 3, 99 95 bytes

Same strategy as @Arnauld's answer.

-4 bytes thanks to @mypetlion

lambda c,s=")0!1@2#3$4%5^6&7*8(9\"'+=,<-_.>/?:;[{\\|]}`~":[c.swapcase(),s[s.find(c)^1]][c in s]

Try it online!

Explanation

• s=")0!1@2#3$4%5^6&7*8(9\"'+=,<-_.>/?:;[{\\|]}`~" contains all pairs of special toggles.
• s[s.index(c)^1] gets the index of the other character from the same pair
• If the character is a Latin or control character (c in s is False), c.swapcase() is returned. c.swapcase() toggles the case of a Latin character, but doesn't affect control character.

Answer 6

APL (Dyalog Extended), 86 bytes^SBCS

This solution has been out-golfed but is preserved due to being interesting for its sourcing of the data.

Anonymous prefix lambda. Requires 0-based indexing (⎕IO←0).

{⍵∊a←↑'[!-~]{2}'⎕S'&'↓⍉↑'\w\w...'⎕R(5⍴'')↓11 71↑30↓⎕FMT⌂notes.keyboards:a⌷⍨~@1⊃⍸⍵=a⋄⍵}

Try it online!

This works by extracting the character pairs from a built-in note about keyboards.

{…} "dfn"; argument character is ⍵:

 ⌂notes.keyboards the built-in string

 ⎕FMT ForMaT as a character matrix

 30↓ drop the first 30 lines

 11 71↑ take the first 11 lines' first 71 columns

 ↓ split into list of strings

 '\w\w...'⎕R(…) PCRE Replace word-character,word-character,any-symbol,any-symbol with:

  '' the empty string

  5⍴ reshaped to length 5, padding with spaces; i.e. 5 spaces

 ↑ mix list of strings into character matrix

 ⍉ transpose

 ↓ split matrix into list of strings

 '[!-~]{2}'⎕R'&' PCRE Search and return any pair of printable ASCII characters

 ↑ mix list of character pairs into two-column matrix

 a← store in a (for all)

 ⍵∊…: if the argument character is a member of that matrix:

  ⍵= Boolean matrix mask where they are equal

  ⍸ get indices where true

  ⊃ pick the first (row,column) pair

  ~@1 negate the number at position 1 (the column; i.e. 1→0 and 0→1)

  a⌷⍨ use that to index into the matrix of all pairs

 ⋄ else:

  ⍵ the argument character

Answer 7

Jelly,  38  37 bytes

“Æz⁶ɦG!€u<ʂCP]ƭƝ’œ?ØṖḟØB¤ḊØD;ṙ21,ƊyŒs

A monadic Link accepting a list of characters which yields a list of characters.

Try it online!

How?

Forms a mapping for non alphabetic characters, applies the translate atom, y, and then swaps case.

“Æz⁶ɦG!€u<ʂCP]ƭƝ’œ?ØṖḟØB¤ḊØD;ṙ21,ƊyŒs - Link: list of characters, S
“Æz⁶ɦG!€u<ʂCP]ƭƝ’                     - base 250 number              =53994992086540427749431907521542401
                        ¤             - nilad followed by link(s) as a nilad:
                   ØṖ                 -   printable characters       = !"#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcdefghijklmnopqrstuvwxyz{|}~
                      ØB              -   base-62 characters         =0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz
                     ḟ                -   filter discard             = !"#$%&'()*+,-./:;<=>?@[\]^_`{|}~
                 œ?                   - lexicographical permutation  = '=<_>?;{|}~)!@#$%^&*("+,-./:[\]`
                         Ḋ            - dequeue                      ='=<_>?;{|}~)!@#$%^&*("+,-./:[\]`
                          ØD          - digit characters             =0123456789
                            ;         - concatenate                  =0123456789'=<_>?;{|}~)!@#$%^&*("+,-./:[\]`
                                 Ɗ    - last three links as a monad:
                              21      -   twenty-one
                             ṙ        -   rotate left                =)!@#$%^&*("+,-./:[\]`0123456789'=<_>?;{|}~
                                ,     -   pair                       =)!@#$%^&*("+,-./:[\]`0123456789'=<_>?;{|}~ and 0123456789'=<_>?;{|}~)!@#$%^&*("+,-./:[\]`
                                  y   - translate (S)
                                   Œs - swap case

Answer 8

Perl 5 -p, 92 91 bytes

-1 byte thanks to @ValueInk

s/[]a-z{}|\\[]/$&^$"/gei;y/0-9)!@#$%^&*(`~\-=_+';":,.\/<>?/)!@#$%^&*(0-9~`_+\-=":';<>?,.\//

Try it online!

Answer 9

05AB1E, 53 36 35 bytes

.šžQžiмDœ•1ĀêŽƵÆ{çIΣeÿí‚Ð"pkālrÙ•è‡

-1 byte implicitly thanks to @Grimmy due to his comment.

Try it online or verify all printable ASCII characters. NOTE: The TIO versions use the S•...•.I (builtin for the n'th permutation of a list) instead of œ•...•è (push all permutations of the string (extremely slow bottleneck for a string this large), and index into it).

Explanation:

.š        # Switch-case of the (implicit) input-character (if it's a letter)
  žQ      # Push all printable ASCII characters:
          #   !"#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcdefghijklmnopqrstuvwxyz{|}~
    žiм   # Remove all letters [A-Za-z]:
          #   !"#$%&'()*+,-./0123456789:;<=>?@[\]^_`{|}~
  D       # Duplicate it
   œ      # Push a list of all permutations of this string
    •1ĀêŽƵÆ{çIΣeÿí‚Ð"pkālrÙ•
         "# Push compressed integer 540470878544692028277787799913384202055137480696656
     è    # Index it into the string-list of permutations:
          #   1'3457"908=<_>?)!@#$%^&*(;:,+./2{|}6-~[\]`
  ‡       # Transliterate the characters at the same indices
          # (after which the result is output implicitly)

See this 05AB1E tip of mine (section How to compress large integers?) to understand why •1ĀêŽƵÆ{çIΣeÿí‚Ð"pkālrÙ• is 540470878544692028277787799913384202055137480696656.

This number(+1) is generated by the Jelly builtin Œ¿, which gets the 1-based index of the permutation.

Answer 10

Pure Bash, 170 bytes

a=`echo {A..Z}`')!@#$%^&*("+,-./:[\]`'
b=`echo {a..z}`0123456789"'=<_>?;{|}~"
c=$a$b
d=$b$a
for((;n<164;n++));do [ "$1" = "${c:n:1}" ]&&echo ${d:n:1}&&exit;done
echo "$1"

Try it online!

I decided to implement a solution inspired by @Noodle9's very nice answer, but using pure bash without any utilities (like tr).

Note that you need to run this in an empty directory; this can be fixed at the cost of 2 bytes by using quotes for "{d:n:1}". (This issue only arises with a non-empty current directory when the input is 8, so the output is supposed to be *.)

On the other hand, you can gain 2 bytes if you don't require output for the input \n: just eliminate the quotes in the final echo.

Answer 11

APL (Dyalog Extended), 60 bytes^SBCS

Anonymous tacit prefix function.

-(,⊃⍨⍳-¯1*⍳)⍨('"''+=,<-_.>/?:;[{\|]}`~',∊')!@#$%^&*(',¨⎕D),-

Try it online!

- swap case

(…), prepend the following:

 ⎕D the digits

 ')!@#$%^&*(',¨ prepend each of these characters to the corresponding digit

 ∊ ϵnlist (flatten)

 '"''+=,<-_.>/?:;[{\|]}`~', prepend these characters ('' is an escaped single quote)

-(…)⍨ apply the following function with that as left argument and the case-swapped original argument as right argument:

 ⍳ ɩndex of the case-swapped argument in the substitution string

 ¯1* negative one raised to that power

 ⍳- subtract that from the ɩndex of the case-swapped argument in the substitution string

 ,⊃⍨ use that to pick an element from the case-swapped argument appended to the substitution string

Answer 12

Pure Bash, 217 bytes

P=printf\ 
a=`$P%x "'$1"`
case $a in 3[ab])x=1;;2[27])x=5;;2[68]|3[79])x=17;;2a|38)x=18;;2b|3d)x=22;;29|30)x=25;;36|5e)x=104;;2d|32|40|5f)x=114;;20|7f)x=0;;60|7e)x=30;;[23]?)x=16;;[4-7]?)x=32
esac
$P\\`$P%o $[0x$a^x]`

Try it online!

Just bash -- no Unix utilities.

Input character is passed as an argument, and the output is on stdout.

_____________________________________________________________

Test runs:

$ cat shifttoggle
P=printf\ 
a=`$P%x "'$1"`
case $a in 3[ab])x=1;;2[27])x=5;;2[68]|3[79])x=17;;2a|38)x=18;;2b|3d)x=22;;29|30)x=25;;36|5e)x=104;;2d|32|40|5f)x=114;;20|7f)x=0;;60|7e)x=30;;[23]?)x=16;;[4-7]?)x=32
esac
$P\\`$P%o $[0x$a^x]`


$cat shifttoggleTest
#!/bin/bash

count=1

for s in ')!@#$%^&*("+,-./:' "0123456789'=<_>?;" ABCDEFGHIJKLMNOPQRSTUVWXYZ abcdefghijklmnopqrstuvwxyz '[\]`' '{|}~' $' \a\n\r\t\x7F\x80\x88\x8F'
  do
    echo "TEST #$count"

    for ((n=0;n<${#s};n++))
      do
        c="${s:$n:1}"
        d=`./shifttoggle "$c"`

    # Backticks remove any trailing newline, so restore that here for the case where c is \n (you can check that shifttoggle really prints \n in that case).
    if test -z "$d"
          then
            d=$'\n'
        fi

    if test "$count" -eq 7
          then
            printf "  ASCII %d => ASCII %d\n" "'$c" "'$d"
      else
            echo "  $c => $d"
        fi

      done

      (( count++ ))
      echo ''
  done


$ ./shifttoggleTest 
TEST #1
  ) => 0
  ! => 1
  @ => 2
  # => 3
  $ => 4
  % => 5
  ^ => 6
  & => 7
  * => 8
  ( => 9
  " => '
  + => =
  , => <
  - => _
  . => >
  / => ?
  : => ;

TEST #2
  0 => )
  1 => !
  2 => @
  3 => #
  4 => $
  5 => %
  6 => ^
  7 => &
  8 => *
  9 => (
  ' => "
  = => +
  < => ,
  _ => -
  > => .
  ? => /
  ; => :

TEST #3
  A => a
  B => b
  C => c
  D => d
  E => e
  F => f
  G => g
  H => h
  I => i
  J => j
  K => k
  L => l
  M => m
  N => n
  O => o
  P => p
  Q => q
  R => r
  S => s
  T => t
  U => u
  V => v
  W => w
  X => x
  Y => y
  Z => z

TEST #4
  a => A
  b => B
  c => C
  d => D
  e => E
  f => F
  g => G
  h => H
  i => I
  j => J
  k => K
  l => L
  m => M
  n => N
  o => O
  p => P
  q => Q
  r => R
  s => S
  t => T
  u => U
  v => V
  w => W
  x => X
  y => Y
  z => Z

TEST #5
  [ => {
  \ => |
  ] => }
  ` => ~

TEST #6
  { => [
  | => \
  } => ]
  ~ => `

TEST #7
  ASCII 32 => ASCII 32
  ASCII 7 => ASCII 7
  ASCII 10 => ASCII 10
  ASCII 13 => ASCII 13
  ASCII 9 => ASCII 9
  ASCII 127 => ASCII 127
  ASCII 128 => ASCII 128
  ASCII 136 => ASCII 136
  ASCII 143 => ASCII 143

Answer 13

C (gcc), 100 bytes

char*strchrnul(),*s=")0@2^6&7*8(9\"'+=-_:;`~\0";f(c){c=s[strchrnul(s,c)-s^1]?:(c%127>32)<<4+c/64^c;}

Similar to the Javascript strategy. I'd like to get rid of the extra parentheses but this is pretty good.

Try it online!

Answer 14

Ruby -p, 66 bytes

Builds the "lowercase" and "uppercase" strings so that everything lines up, and connects them together to be passed into the tr function so it can do the proper conversions.

l="\\-a-z0-9=[-];',./`"
u='_A-Z)!@#$%^&*(+{|}:"<>?~'
$_.tr!u+l,l+u

Try it online!