Invert Some Switches on a Switchboard

Question

Goal:

Given a pre-configured switchboard and a list of indexes, invert the switches at the given indexes.

A switchboard is made up of some number of switches (v or ^) wrapped in -'s and arranged into rows of varying length. Here is an example switchboard:

-v-^-v-
-^-v-
-v-^-v-

To invert/flip a switch means changing it from v to ^, or from ^ to v.

The switches are indexed left-to-right, top-to-bottom. E.g., in the example above, the last v in the first row would be in position 3 and the ^ in the middle row would be at 4 (using 1-indexing).

Input:

A string (or list of strings) representing the switchboard. It is guaranteed to match the regex ((-[v^])+-)(\n(-[v^])+-)*.
A possibly empty list of numbers representing indexes, may be 0 or 1 (or some arbitrary number if you want) indexed. These are the switches that need to be flipped.

Output:

A switchboard in the same shape as the input with the specified switches inverted. Any unspecified switches should retain their initial state.

Rules:

Input will always be correctly formatted and no given indexes will be out of bounds.
The list of indexes will be sorted and will have no duplicates.
State in your answer what indexing you use, be it 0, 1, or some arbitrary one.
Trailing whitespace is fine as long as the output looks like the input.
This is code-golf so shortest code wins.

Examples:

#Using 1-indexing
input: #Empty Case
[],
-v-^-v-

output:
-v-^-v-

input: #Single switch
[1],
-v-

output:
-^-

input: #Skip a line
[3,5],
-^-v-v-
-v-
-^-^-

output:
-^-v-^-
-v-
-v-^-

input: #Flip one in each line + number wrap
[3,4,6],
-^-v-v-
-v-
-^-^-

output:
-^-v-^-
-^-
-^-v-

input: #Flip 'em all
[1,2,3,4,5,6],
-^-v-v-
-v-
-^-^-

output:
-v-^-^-
-^-
-v-v-

Can we output a rectangular char array, right-padding the shorter lines with spaces? Also, can we take input in that form? — Luis Mendo, Commented Jul 24, 2019 at 15:50
@LuisMendo I'm going to say No on taking that as input. Trailing white space is fine as long as it looks like the input. — Veskah, Commented Jul 24, 2019 at 15:57
Hint to those checking if characters are >"-": As the input string is guaranteed to start with -, you can check against the parameter/argument/variable name you're using for that instead. — Shaggy, Commented Jul 25, 2019 at 22:31

DJMcMayhem · Accepted Answer · 2019-07-24 17:01:03Z

11

Vim, 60, 46, 38, 37 bytes/keystrokes

qq/\d
ggDJ@"/[v^]
sv^<esc>l?\V<C-r>"
x@qq4u@q

<esc> and <C-r> are both 1 byte/keystroke. Byte Counter

Test Case 1 (Verbose mode)

Test Case 2 (Verbose mode)

Thanks to Grimy for the ideas that led to a reduction of 22 bytes :)

edited Jul 24, 2019 at 17:01

answered Jul 24, 2019 at 16:02

DJMcMayhem

59.6k17 gold badges196 silver badges348 bronze badges

2

\$\begingroup\$ @Veskah ughhhhhh vim is super finicky about "do something 0 times" edge cases. See edit \$\endgroup\$
– DJMcMayhem
Commented Jul 24, 2019 at 16:32
\$\begingroup\$ Couldn't :s/\%V./\='v^'[submatch(0)=='v'] be cl<C-R>='v^'['<C-R>"'=='v'] for -13 bytes? (each <C-R> is only one byte). \$\endgroup\$
– Grimmy
Commented Jul 24, 2019 at 16:36
2

\$\begingroup\$ @Grimy Ooh, good idea. Also s == cl, so -14 overall. \$\endgroup\$
– DJMcMayhem
Commented Jul 24, 2019 at 16:42
\$\begingroup\$ Other ideas: s^v!<Esc>?\<C-R>"<CR>xhf!x or s<CR>^v<Esc>:s/\V<C-R>"<CR>kgJ. \$\endgroup\$
– Grimmy
Commented Jul 24, 2019 at 16:51
1

\$\begingroup\$ I thought about that, but it fails if the character to be inverted is at the end of a line… but then the input spec guarantees it’s followed by a -, so it actually works! Duh. \$\endgroup\$
– Grimmy
Commented Jul 24, 2019 at 18:13

| Show 1 more comment

Community · Accepted Answer · 2020-06-17 09:04:33Z

6

JavaScript, 63 59 bytes

a=>s=>s.replace(/v|\^/g,x=>"^v"[a.includes(n++)^x>"^"],n=0)

Try it online!

Saved 4 bytes thanks to Arnauld.

edited Jun 17, 2020 at 9:04

CommunityBot

1

answered Jul 24, 2019 at 19:42

Shaggy

43.5k4 gold badges36 silver badges94 bronze badges

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mkst · Accepted Answer · 2019-07-24 21:49:10Z

K (oK), 31 27 bytes

Solution:

`0:{@[x;(&x>93)y;"^v"94=]};

Try it online!

Explanation:

Quick answer, will try to golf it. 0-indexed.

`0:{@[x;(&x>93)y;"^v"94=]}; / the solution
`0:                       ; / print to stdout
   {                     }  / lambda taking 2 implicit args x & y
    @[ ;        ;       ]   / apply @[var;index;function]
                     94=    / 94 (ASCII "v") equal to? returns 0 or 1
                 "v^"       / index into "v^" (ie flip switch)
               y            / index into
        (     )             / do this together
          x>93              / x greater than 93 (ASCII "]")
         &                  / indices where true
      x                     / apply to x

Notes:

-4 bytes thanks to >93 trick

Rin's Fourier transform · Accepted Answer · 2019-07-24 19:32:24Z

3

Python 3, 140 134 103 bytes

(-30 thanks to DJMcMayhem♦, -1 more thanks to Black Owl Kai)

def f(i,y,x=1):
 for c in y:q=c>'-';p=len(i)and x==i[0]*q;print([c,"v^"[c>'^']][p],end='');x+=q;i=i[p:]

Try it online!

Oof, second try at golfing anything at all. This just uses a rather unsophisticated loop over the string, using x to keep track of the current switch index. Uses 1-indexing.

Ungolfed:

def f(i,y):
     x = 1
     for c in y:
         nextchar = c # nextchar gets golfed out completely within the print
         if c in 'v^': # golfed as c>'-'
             if len(i) and x==i[0]:
                nextchar = 'v' if c=='^' else '^'
                i = i[1:]
             x += 1
         print(nextchar, end='')

edited Jul 24, 2019 at 19:32

answered Jul 24, 2019 at 16:51

Rin's Fourier transform

8576 silver badges12 bronze badges

\$\begingroup\$ 107 bytes \$\endgroup\$
– DJMcMayhem
Commented Jul 24, 2019 at 17:49
\$\begingroup\$ 106 bytes \$\endgroup\$
– Kateba
Commented Jul 24, 2019 at 18:11
\$\begingroup\$ Or 104 if python 3 is acceptable \$\endgroup\$
– DJMcMayhem
Commented Jul 24, 2019 at 18:22
\$\begingroup\$ @DJMcMayhem Ooh, thanks for that replace catch xd Would you want to post the Python 3 as a separate answer, or do you think it's similar enough to add as an edit to this? \$\endgroup\$
– Rin's Fourier transform
Commented Jul 24, 2019 at 18:52
1

\$\begingroup\$ Feel free to add it :) I might post a python 3 answer, but I'd probably try to come up with my own approach first. \$\endgroup\$
– DJMcMayhem
Commented Jul 24, 2019 at 19:14

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Jonathan Allan · Accepted Answer · 2019-07-24 23:20:09Z

Jelly, 12 bytes

O^%5T⁴ịƲ¦40Ọ

A full program accepting a string and a list of integers which prints the result.

Try it online!

How?

O^%5T⁴ịƲ¦40Ọ - Main Link: list of characters, S; inversion indices, I
O            - to ordinals   ('\n':10, '-':45, '^':94, 'v':118)
        ¦    - sparse application...
       Ʋ     - ...to indices: last four links as a monad: f(O(S))
  %5         -   modulo 5   (10:0, 45:0, 94:4, 118:3)
    T        -   truthy indices (giving, X, indices of '^' and 'v' in S)
     ⁴       -   4th command line argument = I
      ị      -   index into X   (giving indices of '^' and 'v' to invert in S)
 ^       40  - ...action: XOR with 40   (94:118, 118:94)
           Ọ - from ordinals
             - implicit print

Community · Accepted Answer · 2020-06-17 09:04:33Z

3

Python 3.8 (pre-release), 80, 78, 77, 71, 70 bytes

lambda x,s,i=0:''.join([c,'^v'[c<'v']][c>s and(i:=i+1)in x]for c in s)

-1 byte, thanks to @Shaggy

Try it online!

edited Jun 17, 2020 at 9:04

CommunityBot

1

answered Jul 25, 2019 at 11:47

Hori

3211 silver badge3 bronze badges

1

\$\begingroup\$ c>s saves a byte. \$\endgroup\$
– Shaggy
Commented Jul 25, 2019 at 22:36

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Sean · Accepted Answer · 2019-07-26 23:21:45Z

3

Perl 6, 31 bytes

->$_,\s{S:nth(s){\^|v}=$/~^'('}

Try it online!

(-2 bytes thanks to Jo King)

Perl 6's substitution operator S conveniently takes an nth adverb that accepts not only a single index at which to make the replacement, but a list of them, exactly as needed here.

The replacement is $/ ~^ '(', where $/ is the matched text (either v or ^), ~^ is the stringwise exclusive-or operator, and ( is the character whose bits turn v into ^ and vice versa.

edited Jul 26, 2019 at 23:21

answered Jul 24, 2019 at 18:12

Sean

8,03611 silver badges15 bronze badges

\$\begingroup\$ 31 bytes \$\endgroup\$
– Jo King ♦
Commented Jul 25, 2019 at 2:24

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Luis Mendo · Accepted Answer · 2019-07-24 16:46:32Z

2

MATL, 29 bytes

c!tt45>o2yfi)(2=XK)t106-E-K(!

Try it online! Or verify all text cases.

Input is a cell array of strings and a row vector of numbers, with 1-based indexing. Output is right-padded with spaces.

answered Jul 24, 2019 at 16:46

Luis Mendo

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Chas Brown · Accepted Answer · 2019-07-24 18:34:34Z

2

Python 2, 105 97 91 bytes

lambda a,s:reduce(lambda(t,i),c:(t+[c,'^v'[c<'v']][c>'-'and i in a],i+(c>'-')),s,('',0))[0]

Try it online!

6 bytes saved by ~~stealing~~ using Rin's Fourier transform's c>'-' instead of c in'^v'.

0-indexed.

edited Jul 24, 2019 at 18:34

answered Jul 24, 2019 at 17:54

Chas Brown

9,7571 gold badge13 silver badges39 bronze badges

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Erik the Outgolfer · Accepted Answer · 2019-07-24 19:21:47Z

2

Jelly, 14 bytes

⁾^vḟ$€>”-T⁹ịƲ¦

Try it online!

Full program.

This feels too overlong...

answered Jul 24, 2019 at 19:21

Erik the Outgolfer

40.6k5 gold badges45 silver badges122 bronze badges

\$\begingroup\$ I don't know Jelly so can't figure out how to try it myself but could you replace ”- with the name of the first argument (³?), which is guaranteed to start with a -, instead? \$\endgroup\$
– Shaggy
Commented Jul 25, 2019 at 22:34
\$\begingroup\$ @Shaggy Nope, because > vectorizes. You can see that it doesn't work. \$\endgroup\$
– Erik the Outgolfer
Commented Jul 25, 2019 at 23:24
\$\begingroup\$ ah, that's exactly what I tried :) Didn't know if it was my lack of Jelly knowledge that was the cause or not, though. Don't suppose there's a single character built-in to get the first character of the first argument? \$\endgroup\$
– Shaggy
Commented Jul 25, 2019 at 23:41
\$\begingroup\$ @Shaggy Erm... the only built-ins for command-line arguments are ³, ⁴, ⁵, ⁶ and ⁷, for the first to the fifth CLAs respectively. You can read the Atoms page to find out if a specific built-in function exists. \$\endgroup\$
– Erik the Outgolfer
Commented Jul 25, 2019 at 23:48
\$\begingroup\$ Ah, well, was worth a shot. One day, I will dive into Jelly properly. \$\endgroup\$
– Shaggy
Commented Jul 25, 2019 at 23:50

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recursive · Accepted Answer · 2019-07-24 22:10:36Z

2

Stax, 13 bytes

¿╫╦ÜΦ1▌X○!ΩTæ

Run and debug it

This uses 0-based indices.

Find all indices of the regex [v^].
Index into the index array using the input.
At each result, xor the input's ascii code with 40. This is xor('v', '^').

answered Jul 24, 2019 at 22:10

recursive

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Οurous · Accepted Answer · 2019-07-24 23:53:49Z

2

Clean, 93 bytes

import StdEnv
$i=foldl(\s c=s++[if(any((==)(sum[1\\k<-s|k>'-']))i&&c>'-')if(c>'^')'^''v'c])[]

Try it online!

Defines the function $ :: [Int] -> [Char] -> [Char] taking a zero-indexed list of indices and returning a function that takes the string and returns the altered string.

edited Jul 24, 2019 at 23:53

answered Jul 24, 2019 at 23:40

Οurous

8,1271 gold badge16 silver badges38 bronze badges

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Chas Brown · Accepted Answer · 2019-07-26 21:25:23Z

2

JavaScript (Node.js), 101 98 93 91 77 67 bytes

a=>s=>[...s].map(c=>t+=c>s?"^v"[a.includes(i++)^c>"^"]:c,t=i=``)&&t

Try it online!

10 bytes, thx to suggestions by Shaggy.

Port of my Python answer. Not used to golfing javascript!

edited Jul 26, 2019 at 21:25

answered Jul 24, 2019 at 18:55

Chas Brown

9,7571 gold badge13 silver badges39 bronze badges

\$\begingroup\$ A few quick tweaks \$\endgroup\$
– Shaggy
Commented Jul 25, 2019 at 9:17
\$\begingroup\$ Or 67 bytes by paying forward the saving Arnauld gave me. \$\endgroup\$
– Shaggy
Commented Jul 25, 2019 at 22:27
\$\begingroup\$ @Shaggy: Tips appreciated! Reading now... \$\endgroup\$
– Chas Brown
Commented Jul 26, 2019 at 5:29

Add a comment |

DJMcMayhem · Accepted Answer · 2019-08-05 17:23:02Z

2

V, 20 bytes

ÑñÀ/vüÞ
sv^l?Ö"
xH

Try it online!

Uses some new features, such as Ñ which is incredibly useful.

answered Aug 5, 2019 at 17:23

DJMcMayhem

59.6k17 gold badges196 silver badges348 bronze badges

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Community · Accepted Answer · 2020-06-17 09:04:33Z

JavaScript, 111 bytes

Code

x=>y=>{x.map(i=>eval(`y=y.replace(/(((v|\\^)[^^v]*){${i}})(v|\\^)/,(a,b,c,d,e)=>b+(e<"v"?"v":"^"))`));return y}

Takes input in format f(x)(y) where x is the indices and y is the switchboard. Indices are 0 indexed

Try it online!

Explanation

For each index

x.map(i=>...

construct the regex that finds the index+1 th "^" or "v"

`.../(((v|\\^)[^^v]*){${i}})(v|\\^)/...`

insert it into a string to replace it with the opposite symbol "v"<->"^"

y=y.replace(...,(a,b,c,d,e)=>b+(e<"v"?"v":"^"))

then evaluate the string as a function

eval(...)

After iterating through the indices to switch, return the switchboard

return y

Nick Kennedy · Accepted Answer · 2019-07-24 19:21:20Z

1

Jelly, 17 bytes

⁾^vK;`©⁹e€ky@€⁸¦®

Try it online!

A full program taking the indices as first and string as second argument. Prints the output with the indicated switches flipped.

answered Jul 24, 2019 at 19:21

Nick Kennedy

21.2k3 gold badges17 silver badges43 bronze badges

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Neil · Accepted Answer · 2019-07-24 20:20:09Z

1

Retina 0.8.2, 66 62 bytes

\d+
$*
T`v^`^v`.(?<=\b(?(3)$)(?<-3>1)+(,1+)*(-|¶|(v|\^))+)
1A`

Try it online! Link includes test case. 1-indexed. Explanation:

\d+
$*

Convert the input numbers to unary.

T`v^`^v`.(?<=\b(?(3)$)(?<-3>1)+(,1+)*(-|¶|(v|\^))+)

Transliterate between v and ^ all characters with the property that the number of vs and ^s so far (inclusive) equals one of the input numbers.

1A`

Delete the input numbers.

edited Jul 24, 2019 at 20:20

answered Jul 24, 2019 at 19:05

Neil

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Neil · Accepted Answer · 2019-07-24 20:36:18Z

Charcoal, 23 bytes

⭆η⎇№θ⌕ΦＬη№v^§ηλκ§v^⁼vιι

Try it online! Link is to verbose version of code. 0-indexed. Explanation:

 η                      Input string
⭆                       Map over characters and join
  ⎇                     If
   №                    Count of (i.e. exists)
     ⌕                  Index of
               κ        Current index in
       Ｌ                Length of
        η               Input string
      Φ                 Implicit range filtered by
         №              Count of (i.e. exists)
             η          Input string
            §           Indexed by
              λ         Current value
          v^            In literal string `v^`
    θ                   In input list
                 v^     Then literal `v^`
                §       Indexed by
                     ι  Current character
                   ⁼    Equal to
                    v   Literal `v`
                      ι Else current character

Value Ink · Accepted Answer · 2019-07-24 20:49:38Z

1

Ruby, 56 bytes

1-indexed.

->s,i{j=0;s.gsub(/[v^]/){i==i-[j+=1]?$&:"v^".tr($&,'')}}

Try it online!

answered Jul 24, 2019 at 20:49

Value Ink

12.6k1 gold badge17 silver badges42 bronze badges

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Gymhgy · Accepted Answer · 2019-07-26 13:49:51Z

1

C# (Visual C# Interactive Compiler), 73 bytes

a=>b=>{int i=0;return a.Select(x=>x>45&&b.Contains(++i)?(char)(x^40):x);}

Try it online!

edited Jul 26, 2019 at 13:49

answered Jul 26, 2019 at 13:39

Gymhgy

8,02811 silver badges35 bronze badges

1

\$\begingroup\$ @Veskah Updated to include empty case \$\endgroup\$
– Gymhgy
Commented Jul 26, 2019 at 13:50

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Community · Accepted Answer · 2020-06-17 09:04:33Z

1

Japt, 15 bytes

®c^(Z>V©øT° *#(

Try it

®c^(Z>V©ø°T *#(    U = Input String, V = Array of Indices
®                  Map each Z in U
 c^                   XOR Z's charcode by
   (Z>V                 Z is 'v' or '^'
      ©                 Short-circuiting Logical and
       øT°              The current Z's index is in V
             *#(        Multiply the boolean with 40 (false = 0, true = 1)

edited Jun 17, 2020 at 9:04

CommunityBot

1

answered Jul 26, 2019 at 13:27

Gymhgy

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Community · Accepted Answer · 2020-06-17 09:04:33Z

1

Japt, 16 14 bytes

Ëc^#(*(D>V©øT°

Try it

Ë>V©øT° ?Dc^#(:D     :Implicit input of multi-line string U & integer array V
Ë                    :Map each D in U
 >V                  :  Greater than V? (Coerces V to a string and, conveniently, all digits are > "\n" & "-" and < "^" & "v")
   ©                 :  Logical AND with
    ø                :  Does V contain
     T°              :    T (initially 0) postfix incremented
        ?            :  If true
         Dc          :  Charcode of D
           ^#(       :  XOR with 40
              :D     :  Else D

edited Jun 17, 2020 at 9:04

CommunityBot

1

answered Jul 24, 2019 at 20:37

Shaggy

43.5k4 gold badges36 silver badges94 bronze badges

\$\begingroup\$ Aw, your code is no longer happy (it lost the :D) \$\endgroup\$
– Veskah
Commented Jul 31, 2019 at 12:14

Add a comment |

Stack Exchange Network

Invert Some Switches on a Switchboard

Goal:

Input:

Output:

Rules:

Examples:

22 Answers 22

Vim, 60, 46, 38, 37 bytes/keystrokes

JavaScript, 63 59 bytes

K (oK), 31 27 bytes

Python 3, 140 134 103 bytes

Jelly, 12 bytes

How?

Python 3.8 (pre-release), 80, 78, 77, 71, 70 bytes

Perl 6, 31 bytes

MATL, 29 bytes

Python 2, 105 97 91 bytes

Jelly, 14 bytes

Stax, 13 bytes

Clean, 93 bytes

JavaScript (Node.js), 101 98 93 91 77 67 bytes

V, 20 bytes

JavaScript, 111 bytes

Code

Explanation

Jelly, 17 bytes

Retina 0.8.2, 66 62 bytes

Charcoal, 23 bytes

Ruby, 56 bytes

C# (Visual C# Interactive Compiler), 73 bytes

Japt, 15 bytes

Japt, 16 14 bytes

Your Answer

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

Linked

Hot Network Questions

Invert Some Switches on a Switchboard

Goal:

Input:

Output:

Rules:

Examples:

22 Answers 22

Vim, 60, 46, 38, 37 bytes/keystrokes

JavaScript, 63 59 bytes

K (oK), 31 27 bytes

Python 3, 140 134 103 bytes

Jelly, 12 bytes

How?

Python 3.8 (pre-release), 80, 78, 77, 71, 70 bytes

Perl 6, 31 bytes

MATL, 29 bytes

Python 2, 105 97 91 bytes

Jelly, 14 bytes

Stax, 13 bytes

Clean, 93 bytes

JavaScript (Node.js), 101 98 93 91 77 67 bytes

V, 20 bytes

JavaScript, 111 bytes

Code

Explanation

Jelly, 17 bytes

Retina 0.8.2, 66 62 bytes

Charcoal, 23 bytes

Ruby, 56 bytes

C# (Visual C# Interactive Compiler), 73 bytes

Japt, 15 bytes

Japt, 16 14 bytes

Your Answer

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

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Hot Network Questions

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