Space Cleaners!

Question

A space cleaner is a special character which removes all spaces between it and the first non space character to its left and it is represented by a '!' character. If it reaches the beginning of the string it stops.

Given a string output the string in any reasonable format after the cleaning process.

Trailing spaces at the end of the string must be still be in the output.

Remember that space cleaners remain after their job.

Input will only consist of printable ASCII characters.

This is code-golf, so least number of bytes win.

Test Cases

" ! a! !b c!d !" => "! a!!b c!d!"
"a    !" => "a!"
"!    a" => "!    a"
"!    !    !" => "!!!"
"! " => "! "

Some test cases would be good. I assume that the cleaners are represented by !s, since it isn't quite clear. So basically, this boils down to "remove any spaces before a space cleaner", correct? — Jo King, Sep 10, 2019 at 6:07
Can we get some examples? What is the minimum string length? What do we do with the input string !? This looks like it would be trivially solved by a regex looking for any number of spaces followed by a bang? — mkst, Sep 10, 2019 at 6:08

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

8

05AB1E, 5 bytes

„ !¤:

Try it online!

Explanation

„ !                  # 2 char string " !"
   ¤                 # Push the tail of that (so "!") 
    :                # Infinite replacement

edited Jun 17, 2020 at 9:04

CommunityBot

1

answered Sep 10, 2019 at 7:29

Expired Data

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

5

Retina, 5 bytes

 +!
!

Try it online.

Not much to say. Simply removes all spaces in front of every ! with a simple replace.

edited Jun 17, 2020 at 9:04

CommunityBot

1

answered Sep 10, 2019 at 6:41

Kevin Cruijssen

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\$\begingroup\$ 4th test case ! ! ! -> !!! why not ! !! ? \$\endgroup\$
– Nahuel Fouilleul
Sep 10, 2019 at 7:12
4

\$\begingroup\$ @NahuelFouilleul Why not? I assume all space cleaners 'walk' simultaneously, so eventually they'll reach the start of the string for that test case. OP never stated the left one walks first, only that all space cleaners travel left. \$\endgroup\$
– Kevin Cruijssen
Sep 10, 2019 at 7:17
1

\$\begingroup\$ maybe the OP should clarify \$\endgroup\$
– Nahuel Fouilleul
Sep 10, 2019 at 7:21
1

\$\begingroup\$ The assumption is correct. (Which, if I'm not mistaken, is equivalent to "the left ones first".) \$\endgroup\$
– null
Sep 10, 2019 at 9:48

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Matsyir · Accepted Answer · 2019-09-12 14:50:35Z

5

JavaScript (ES6), 24 bytes

^{Thanks to @Nick Kennedy for the TIO link and -2 bytes, since I could omit the function name f=}

_=>_.replace(/ +!/g,'!')

Try It Online

Nothing special, same regex as other answers. New to codegolf, was a simple one to translate to js. If anyone can think of improvements I'd love to see them.

edited Sep 12, 2019 at 14:50

answered Sep 11, 2019 at 16:50

Matsyir

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\$\begingroup\$ Welcome to the site! \$\endgroup\$
– Wheat Wizard ♦
Sep 11, 2019 at 16:58
1

\$\begingroup\$ Welcome to the site! I like the underline obfuscation LOL. \$\endgroup\$
– null
Sep 12, 2019 at 5:35
\$\begingroup\$ Welcome! Would suggest having a Try it online link with a working example. Also you can move the naming of the lambda to a header and remove it from the byte count. e.g. tio.run/##BcExDoAgDADAr7QsQFRYXfArBCsQDREChu/… \$\endgroup\$
– Nick Kennedy
Sep 12, 2019 at 13:38
\$\begingroup\$ @NickKennedy Thanks! I wasn't sure about the function naming, good to know. I considered the TIO link but figured it's easy enough to test JS with browser console. Although, I will edit it into my post. \$\endgroup\$
– Matsyir
Sep 12, 2019 at 13:52

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Night2 · Accepted Answer · 2019-09-11 09:41:18Z

4

PHP, 35 bytes

<?=preg_replace('/ +!/','!',$argn);

Try it online!

Just a simple RegEx replace.

answered Sep 11, 2019 at 9:41

Night2

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Sumner18 · Accepted Answer · 2019-09-11 13:04:21Z

4

R, 25 bytes

gsub(" +!","!",scan(,''))

Straightforward enough with a simple regex substitution!

Try it online!

answered Sep 11, 2019 at 13:04

Sumner18

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Jo King · Accepted Answer · 2019-09-12 01:58:46Z

4

Haskell, 48 42 bytes

-6 bytes thanks to H.PWiz!

g(' ':b)|'!':_<-g b=g b
g(a:b)=a:g b
g a=a

Try it online!

Explanation:

g(' ':b)                 -- Given a string starting with space
        |'!':_           -- Check if '!' is the first element of
              <-g b      -- The function applied to the rest of it
                   =g b  -- Return the function applied to the rest of it
g(a:b)=a:g b             -- Otherwise just apply the function recursively
g a=a                    -- Until the string is empty

edited Sep 12, 2019 at 1:58

answered Sep 11, 2019 at 12:52

Jo King♦

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\$\begingroup\$ You don't need parens around g b. Also, you can replace g b!!0=='!' with '!':_<-g b \$\endgroup\$
– H.PWiz
Sep 12, 2019 at 1:42

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Jitse · Accepted Answer · 2019-09-10 08:14:33Z

3

Python 3, 50 bytes

f=lambda s:' !'in s and f(s.replace(' !','!'))or s

Try it online!

Port of Expired Data's 05AB1E answer, so make sure to upvote him!

Original answer:

Python 3, 63 bytes

lambda s:'!'.join(i.rstrip(' ')for i in(s+'_').split('!'))[:-1]

Try it online!

edited Sep 10, 2019 at 8:14

answered Sep 10, 2019 at 7:10

Jitse

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\$\begingroup\$ Isn't just using regex easier and shorter? \$\endgroup\$
– Kevin Cruijssen
Sep 10, 2019 at 7:20
\$\begingroup\$ @KevinCruijssen Yes, for sure! I just like to try without. \$\endgroup\$
– Jitse
Sep 10, 2019 at 7:22

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Jo King · Accepted Answer · 2019-09-11 03:39:33Z

3

brainfuck, 66 bytes

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

Try it online!

It's funny how much space is just taken up by constants, in this case making a space takes up more than a quarter of the code.

answered Sep 11, 2019 at 3:39

Jo King♦

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xnor · Accepted Answer · 2019-09-12 07:00:00Z

3

Haskell, 34 bytes

foldr(%)""
' '%r@('!':_)=r
c%s=c:s

Try it online!

answered Sep 12, 2019 at 7:00

xnor

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roblogic · Accepted Answer · 2019-09-15 13:42:02Z

3

ksh, 18 bytes

try it online!

echo ${1//+( )!/!}

zsh, 32 bytes
_{Since there's another zsh answer I changed to ksh. Thanks to @Gilles at unix.se for zsh help. try it online!}
setopt ksh_glob;<<<${1//+( )!/!}

edited Sep 15, 2019 at 13:42

answered Sep 13, 2019 at 17:49

roblogic

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AviFS · Accepted Answer · 2021-06-22 06:47:05Z

///, 6 bytes

/ !/!/

Try it online!

Replaces every occurrence of ! with ! until it eats up all the spaces in front of the exclamation marks.

The language is a perfect match because it's built on find/replace. That's the only command you're given, and not a single special character or wild card to use in your patterns, except the \ which only serves to escape the /. Yet, it's Turing complete. It's really elegant!

The language is read by slash triplets, hence the name. Each one couches a find pattern and replace pattern. We have one such pattern here doing precisely what it says at the top. The first pair of slashes says to find all ! and the second pair says to replace them with !.

\$\begingroup\$ What I intended. But input: / :( \$\endgroup\$
– null
Jul 26, 2021 at 16:07 — null, Jul 26, 2021 at 16:07

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

2

Perl 5 (`-p`), 9 bytes

s/ *!/!/g

TIO

edited Jun 17, 2020 at 9:04

CommunityBot

1

answered Sep 10, 2019 at 7:16

Nahuel Fouilleul

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Veskah · Accepted Answer · 2019-09-12 14:52:52Z

2

PowerShell, 22 bytes

$args-replace' +!','!'

Try it online!

answered Sep 12, 2019 at 14:52

Veskah

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Nick Kennedy · Accepted Answer · 2019-09-12 23:10:46Z

2

Jelly, 11 bytes

œṣ⁾ !j”!µÐL

Try it online!

answered Sep 12, 2019 at 23:10

Nick Kennedy

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Triggernometry · Accepted Answer · 2019-09-13 14:22:52Z

2

Python 3, 38 bytes

lambda s:re.sub(' +!','!',s)
import re

A simple regex substitution. Replaces any amount of space plus an exclamation mark with just an exclamation mark.

edited Sep 13, 2019 at 14:22

answered Sep 11, 2019 at 17:12

Triggernometry

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\$\begingroup\$ Why using a raw string? lambda s:re.sub(' *!','!',s) is a byte shorter. \$\endgroup\$
– Skillmon
Sep 13, 2019 at 13:44
\$\begingroup\$ @Skillmon Man, that habit is hard to break for code golf. Thanks for pointing it out! \$\endgroup\$
– Triggernometry
Sep 13, 2019 at 14:22

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Gilles 'SO- stop being evil' · Accepted Answer · 2019-09-13 19:07:59Z

2

Zsh with `extended_glob`, 14 bytes

<<<${1// #!/!}

Zsh with extended_glob is not an arbitrary whim: it's the language in which zsh completion functions are written. Inspired by roblogic's initial attempt. Try it online.

answered Sep 13, 2019 at 19:07

Gilles 'SO- stop being evil'

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Neil · Accepted Answer · 2019-09-15 18:44:17Z

Charcoal, 22 bytes

≔ ηＦ⮌Ｓ«≡ι!≔ωη ≔ηι≔ η←ι

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

≔ η

h is a variable that specifies whether a space is being cleaned or not.

Ｆ⮌Ｓ«

Loop over the string in reverse as the spaces are cleaned to the left.

≡ι

Switch over the current character.

!≔ωη

If it's a ! then start cleaning spaces.

 ≔ηι

If it's a space then replace it with the space cleaning flag.

≔ η

Otherwise turn off space cleaning.

←ι

Print the current character leftwards.

Boring 15-byte version:

Ｗ№θ !≔⪫⪪θ !¦!θθ

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

Ｗ№θ !

Repeat while there are spaces to be cleaned.

≔⪫⪪θ !¦!θ

Clean up to one space per space cleaner.

θ

Output the result.

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

1

Japt, 7 bytes

Recursive replacement. Could save 2 bytes if we could choose the "cleaner" character.

e" !"'!

Try it

edited Jun 17, 2020 at 9:04

CommunityBot

1

answered Sep 10, 2019 at 11:46

Shaggy

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\$\begingroup\$ I didn't get how did you save bytes by changing the cleaner character. \$\endgroup\$
– null
Sep 10, 2019 at 13:20
\$\begingroup\$ @TwilightSparkle, Japt has constants for a few characters & digits (e.g., T===0), which would allow me to do something like eS+TT (where S is Japt's constant for a single space). \$\endgroup\$
– Shaggy
Sep 10, 2019 at 13:29
\$\begingroup\$ Thanks for the explanation. I choose ! just because it's next to the space in the ASCII table. \$\endgroup\$
– null
Sep 11, 2019 at 13:31

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Jo King · Accepted Answer · 2019-09-11 03:07:45Z

1

Perl 6, 14 bytes

{S:g/\s+\!/!/}

Try it online!

Loses bytes over other regex solutions since I can't use a literal space and I have to escape the metaoperator !

answered Sep 11, 2019 at 3:07

Jo King♦

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Jonah · Accepted Answer · 2019-09-12 04:21:49Z

1

J, 16 bytes

(#~1-' !'E.])^:_

Try it online!

answered Sep 12, 2019 at 4:21

Jonah

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AZTECCO · Accepted Answer · 2019-09-12 05:06:34Z

1

C (clang), 79 bytes

j,e;f(char*s){for(j=e=0;!e;e=!*s++)*s-32?s-=*s-33?j:0,j=0,*s&&putchar(*s):j++;}

Try it online!

Saved 1 thanks to @ceilingcat *s && instead of !*s ||

j is used to jump back if there is no "!" after spaces.

edited Sep 12, 2019 at 5:06

answered Sep 11, 2019 at 3:07

AZTECCO

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Value Ink · Accepted Answer · 2019-09-13 20:21:21Z

1

Ruby `-p`, 14 bytes

gsub(/ +!/,?!)

Unfortunately the 13-byte gsub / +!/,?! doesn't work because Ruby interprets the first / as division instead of the start of a regex statement.

Try it online!

answered Sep 13, 2019 at 20:21

Value Ink

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Benjamin Urquhart · Accepted Answer · 2019-09-15 13:31:14Z

1

Java 8+, 26 bytes

Yet another regex port

s->s.replaceAll(" +!","!")

TIO

edited Sep 15, 2019 at 13:31

answered Sep 14, 2019 at 22:59

Benjamin Urquhart

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1

\$\begingroup\$ I think lambdas where first introduced in Java 8. \$\endgroup\$
– Jonathan Frech
Sep 14, 2019 at 23:39
\$\begingroup\$ @JonathanFrech I had a brain short-circuit there \$\endgroup\$
– Benjamin Urquhart
Sep 15, 2019 at 13:31

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Razetime · Accepted Answer · 2020-09-19 15:22:41Z

1

Pip, 8 bytes

aRw.'!'!

Try it online!

concatenates the whitespace regex variable w with an ! character. then replaces it with a single ! in the string.

answered Sep 19, 2020 at 15:22

Razetime

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LegionMammal978 · Accepted Answer · 2020-10-31 20:19:12Z

1

Husk, 8 bytes

ωσ" !""!

Try it online!

answered Oct 31, 2020 at 20:19

LegionMammal978

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cnamejj · Accepted Answer · 2021-06-15 08:24:58Z

1

AWK, 16 bytes

gsub(" *!","!")1

Try it online!

Similar regex to some others that were posted, just AWK-styled. Adding a random number on the end makes sure it prints even if the input has no cleaner character.

answered Jun 15, 2021 at 8:24

cnamejj

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emanresu A · Accepted Answer · 2021-06-15 06:38:53Z

0

Vyxal, 9 bytes

` *!`\!øṙ

Try it Online!

Another one ports the regex

answered Jun 15, 2021 at 6:38

emanresu A

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Space Cleaners!

Test Cases

27 Answers 27

05AB1E, 5 bytes

Explanation

Retina, 5 bytes

JavaScript (ES6), 24 bytes

PHP, 35 bytes

R, 25 bytes

Haskell, 48 42 bytes

Explanation:

Python 3, 50 bytes

Python 3, 63 bytes

brainfuck, 66 bytes

Haskell, 34 bytes

ksh, 18 bytes

///, 6 bytes

Perl 5 (`-p`), 9 bytes

PowerShell, 22 bytes

Jelly, 11 bytes

Python 3, 38 bytes

Zsh with `extended_glob`, 14 bytes

Charcoal, 22 bytes

Japt, 7 bytes

Perl 6, 14 bytes

J, 16 bytes

C (clang), 79 bytes

Ruby `-p`, 14 bytes

Java 8+, 26 bytes

Pip, 8 bytes

Husk, 8 bytes

AWK, 16 bytes

Vyxal, 9 bytes

Your Answer

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

Hot Network Questions

Space Cleaners!

Test Cases

27 Answers 27

05AB1E, 5 bytes

Explanation

Retina, 5 bytes

JavaScript (ES6), 24 bytes

PHP, 35 bytes

R, 25 bytes

Haskell, 48 42 bytes

Explanation:

Python 3, 50 bytes

Python 3, 63 bytes

brainfuck, 66 bytes

Haskell, 34 bytes

ksh, 18 bytes

///, 6 bytes

Perl 5 (-p), 9 bytes

PowerShell, 22 bytes

Jelly, 11 bytes

Python 3, 38 bytes

Zsh with extended_glob, 14 bytes

Charcoal, 22 bytes

Japt, 7 bytes

Perl 6, 14 bytes

J, 16 bytes

C (clang), 79 bytes

Ruby -p, 14 bytes

Java 8+, 26 bytes

Pip, 8 bytes

Husk, 8 bytes

AWK, 16 bytes

Vyxal, 9 bytes

Your Answer

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Hot Network Questions

Perl 5 (`-p`), 9 bytes

Zsh with `extended_glob`, 14 bytes

Ruby `-p`, 14 bytes