Toggle a string

Question

The challenge involve simply toggling a string within another string.

Explanation

If the toggle string is a substring of the main string, remove all instances of the toggle string from the main string; otherwise, append the toggle string at the end of the main string.

Rules

• All string are composed of printable ASCII characters
• The function should take two parameters: the main string and the toggle string.
• The main string can be empty.
• The toggle string cannot be empty.
• The result should be a string, which can be empty.
• The shortest answer wins.

Examples

function toggle(main_string, toggle_string){ ... }

toggle('this string has 6 words ', 'now') 
=> 'this string has 6 words now'

toggle('this string has 5 words now', ' now') 
=> 'this string has 5 words'

Tests cases

'','a'          => 'a'
'a','a'         => ''

'b','a'         => 'ba'
'ab','a'        => 'b'

'aba','a'       => 'b'
'ababa', 'aba'  => 'ba'

Answer 1

Java 8, 80 70 65 34 bytes

t->m->m==(m=m.replace(t,""))?m+t:m

Probably my shortest Java 'codegolf' so far.. xD
with some help from the comments.. ;)

Explanation:

Try it online.

t->m->                     // Method with two String parameters and String return-type
                           // (NOTE: Takes the toggle `t` and main `m` in reversed order)
  m==(m=m.replace(t,""))?  //  If `m` equals `m` with all `t`-substrings removed:
                           //  (And set `m` to `m` with all `t`-substrings removed)
   m+t                     //   Output this new `m` concatted with `t`
  :                        //  Else:
   m                       //   Output just this new `m`

Answer 2

MATL, 11 bytes

yyXf?''YX}h

Try it Online!

All test cases

Explanation

            % Implicitly grab the main string
            % Implicitly grab the toggle string
y           % Copy the main string
y           % Copy the toggle string
Xf          % Check to see if the toggle string is present in the main string
?           % If so
    ''YX    % Replace with an empty string
}           % else
    h       % Horizontally concatenate the two strings
            % Implicit end of if...else
            % Implicitly display the result

Answer 3

Python 3, 38 bytes

lambda s,t:(s+t,s.replace(t,""))[t in s]

Answer 4

Jelly, 7 bytes

œṣȮ⁸e⁹ẋ

Try it online!

How it works

œṣȮ⁸e⁹ẋ  Main link. Arguments: s (string), t (toggle string)

œṣ       Split s at occurrences of t.
  Ȯ      Print the result.
   ⁸e    Check if s occurs in the split s. Yields 1 (true) or 0 (false).
     ⁹ẋ  Repeat t that many times.

Answer 5

JavaScript (ES6), 39 37 bytes

(s,t,u=s.split(t).join``)=>u==s?s+t:u

Answer 6

Pyke, 14 bytes

DX{iIXRk:)i!IJ

Try it here!

Given that Pyke has no else structure, I think this is pretty reasonable score

Explanation:

D              -    Duplicate input
 X             -   a,b = ^
  {            -  a in b
   i           - i = ^
    I          - if i:
     XRk:      -  a = b.replace(a,"")
         i!I   - if not i:
            J  -  a = "".join(input)
               - print a

Answer 7

CJam, 9

q~:B/2Be]

Try it online. Thanks jimmy23013 for chopping off 1 byte :)

Explanation:

q~     read and evaluate the input (given as 2 quoted strings)
:B     store the toggle string in B
/      split the main string by the toggle string
2Be]   pad the array of pieces to the right with B, up to length 2 (if shorter)

Answer 8

Javascript (ECMAScript 6): 47 bytes

(a,b)=>(c=a.replace(RegExp(b,'g'),''))!=a?c:a+b

Answer 9

Retina, 38 31 bytes

Byte count assumes ISO 8859-1 encoding.

(.+)(?=.*¶\1$)
·
1>`·|¶.+

T`·¶

The trailing linefeed is significant. Input format is both strings separated with a linefeed.

Try it online! The first line allows running several test cases at once (for the test suite, use ; to separate the strings and linefeeds to separate test cases; the first line takes care of the conversion).

Explanation

(.+)(?=.*¶\1$)
·

In this first step we replace all occurrences of the toggle string in the main string with ·. We need to insert these markers so that we can determine afterwards if any substitution happened.

1>`·|¶.+

This is another substitution which removes a · marker, or the second line (including the separating linefeed). However, the 1> is a limit which means that only matches after the first are considered. Hence, if the toggle string did not occur in the main string, we won't have inserted any ·, so the second line will be the first match and won't be removed. Otherwise, we remove the second line along with all but the first marker.

T`·¶

While this uses a transliteration stage, it's also used simply for removing characters. In particular, we move both · and linefeeds. We need the first one, in case there was a match (because then the first · will have been left behind by the previous stage) and we need the second one in case there wasn't a match (to join the two lines together and thereby append the toggle string to the main string).

Answer 10

Python (3.4): 55 54 47 44 Bytes

lambda m,t:m.replace(t,'')if t in m else m+t

Testing:

toggle=lambda m,t:m.replace(t,'')if t in m else m+t
print('', 'a', toggle('','a'))
print('a', 'a', toggle('a','a'))
print('b', 'a', toggle('b','a'))
print('ab', 'a', toggle('ab','a'))
print('aba', 'a', toggle('aba','a'))
print('ababa', 'aba', toggle('ababa','aba'))

The Test output

 a a
a a
b a ba
ab a b
aba a b
ababa aba ba

Using a def would be longer because you have to use a return statement, if it were possible without return it would save 2 Bytes Since explicit declaration of the function is not needed (sorry I didn't know that) 7 Bytes were saved.

Answer 11

C#, 63

string F(string s,string t)=>s.Contains(t)?s.Replace(t,""):s+t;

Better than Java :)

Test code:

public static void Main()
{
    Console.WriteLine(F("", "a"));
    Console.WriteLine(F("a", "a"));
    Console.WriteLine(F("b", "a"));
    Console.WriteLine(F("ab", "a"));
    Console.WriteLine(F("aba", "a"));
    Console.WriteLine(F("ababa", "aba"));
    Console.ReadLine();
}

Output:

a

ba
b
b
ba

Answer 12

Pyth, 13 11 10 bytes

?/Qz:Qzk+z

Test suite.

Input format: first string in quotes, second string without quotes.

This is also 10 bytes:

?tJcQzsJ+z

Test suite.

This is 11 bytes:

pscQz*!}zQz

Test suite.

Previous 13-byte solution:

?:IQzk+Qz:Qzk

Test suite.

Answer 13

Jolf, 12 bytes

?=iγρiIE+iIγ

Or, if we must include regex-sensitive chars:

?=iγρiLeIE+iIγ

Try it here!

Explanation

?=iγρiIE+iIγ    if(i === (γ = i.replace(I, E))) alert(i + I); else alert(γ);
  i                i
 =                   ===
    ρ                          .replace( ,  )
     iI                       i         I 
       E                                   E
   γ                     (γ =                )
?               if(                           )
        +iI                                     alert(i + I);
                                                              else
           γ                                                       alert(γ);

Answer 14

JavaScript (ES6), 37 Bytes

(m,t)=>(w=m.split(t).join``)==m?m+t:w

Slightly shorter than @nobe4 's answer by taking advantage of split and join

Answer 15

Racket, 70 bytes

Pretty straight forward.

(λ(s t)((if(string-contains? s t)string-replace string-append)s t""))

Answer 16

Scala, 72 70 bytes

def x(m:String,s:String)={val r=m.replaceAll(s,"");if(r==m)m+s else r}

Online interpreter: www.tryscala.com

Answer 17

Oracle SQL 11.2, 66 bytes

SELECT DECODE(:1,s,s||:2,s)FROM(SELECT REPLACE(:1,:2)s FROM DUAL);

Answer 18

Ruby, 33 bytes 27 bytes (28 if using global subtitution) definitely 28 bytes

->u,v{u[v]?u.gsub(v,''):u+v}

Answer 19

Ruby, 35 37 28 bytes

->m,t{m[t]?m.gsub(t,''):m+t}

Hooray for string interpolation! It even works in regexes. The rest is simple: if the string in t matches to m, replace t with '', else return m+t.

Edit: Fixed a bug.

Edit: I applied Kevin Lau's suggestion, but it appears that I have reached the same algorithm as the one used in Luis Masuelli's answer.

Answer 20

Perl, 37 30 bytes

{$_=shift;s/\Q@_//g?$_:"$_@_"}

Regular expressions inside the toggle string are not evaluate because of the quoting with \Q...\E.

sub F and \E are removed according to the comment by msh210.

It is not entirely free of side effects because of setting $_. Using a local variable will cost six additional bytes:

{my$a=shift;$a=~s/\Q@_//g?$a:"$a@_"}

On the other hand, with switched input parameters two bytes can be saved by using pop instead of shift (28 bytes):

{$_=pop;s/\Q@_//g?$_:"$_@_"}

Test file:

#!/usr/bin/env perl

sub F{$_=shift;s/\Q@_//g?$_:"$_@_"}

sub test ($$$) {
  my ($m, $t, $r) = @_;
  my $result = F($m, $t);
  print "F('$m', '$t') -> '$result' ",
    ($result eq $r ? '=OK=' : '<ERROR>'), " '$r'\n";
}
test '', 'a', 'a';
test 'a', 'a', '';
test 'b', 'a', 'ba';
test 'ab', 'a', 'b';
test 'aba', 'a', 'b';
test 'ababa', 'aba', 'ba';
test 'ababa', 'a*', 'ababaa*';
test 'foobar', '.', 'foobar.';
__END__

Test result:

F('', 'a') -> 'a' =OK= 'a'
F('a', 'a') -> '' =OK= ''
F('b', 'a') -> 'ba' =OK= 'ba'
F('ab', 'a') -> 'b' =OK= 'b'
F('aba', 'a') -> 'b' =OK= 'b'
F('ababa', 'aba') -> 'ba' =OK= 'ba'
F('ababa', 'a*') -> 'ababaa*' =OK= 'ababaa*'
F('foobar', '.') -> 'foobar.' =OK= 'foobar.'

Answer 21

C# (58 bytes)

string F(string s,string t)=>s==(s=s.Replace(t,""))?s+t:s;

It uses an inline assignment to shave a few bytes off

Answer 22

bash + sed, 28 bytes

sed "s/$2//g;t;s/$/$2/"<<<$1

The script lives in a toggle-string.bash file, which we call with bash toggle-string.bash mainstring togglestring.

s/$2//g removes the toggle string from the main string

t jumps to the end if the previous substitution was successful (ie. the main string contained the toggle string)

/$/$2/ adds the toggle string at the end ($), if we didn't jump to the end

bash is required for the herestring

Answer 23

Julia, 33 31 bytes

s|t=(r=replace(s,t,""))t^(s==r)

Try it online!

Answer 24

PowerShell v2+, 47 bytes

param($a,$b)(($c=$a-replace$b),"$a$b")[$c-eq$a]

Takes input $a,$b and then uses a pseudo-ternary (... , ...)[...] statement to perform an if/else. The inner parts are evaluated first to form an array of two elements. The 0th is $a with all occurrences of $b -replaced with nothing, which is stored into $c. The 1st is just a string concatenation of $a and $b.

If $c is -equal to $a, meaning that $b wasn't found, that's Boolean $true or 1, and so the 1st element of the array (the concatenation) is chosen. Else, it's Boolean $false, so we output $c, the 0th element.

Note that -replace is greedy, so it will replace from the left first, meaning the ababa / aba test case will properly return ba.

Answer 25

Java 8, 65 bytes

BinaryOperator<String>l=(m,t)->m.contains(t)?m.replace(t,""):m+t;

The same logic as the Java 7 solution, written with a lambda.

Try it here

Answer 26

Mathematica, 45 bytes

If[StringContainsQ@##,StringDelete@##,#<>#2]&

Anonymous function that takes the main string and the toggle string (in that order) and returns the result. Explanation:

                                            &  Anonymous function returning...

If[StringContainsQ@##,               ,     ]    if its first argument contains
                                                its second argument, then...
                      StringDelete@##            its first argument with its
                                                 second argument removed, else...
                                      #<>#2      its second argument appended to
                                                 its first argument.

Answer 27

TSQL, 143 129 121 Bytes

DECLARE @1 VARCHAR(10)='',@2 VARCHAR(10)='a'SELECT CASE WHEN @1 LIKE'%'+@2+'%'THEN REPLACE(@1,@2,'')ELSE CONCAT(@1,@2)END

Readable:

   DECLARE @1 VARCHAR(10) = ''
    , @2 VARCHAR(10) = 'a'

SELECT CASE WHEN @1 LIKE '%' + @2 + '%'
            THEN REPLACE(@1, @2, '')
            ELSE CONCAT (@1, @2)
            END

Live Demo

114 Bytes with strictly 1 character input

DECLARE @1 CHAR(1) = 'a'
    , @2 CHAR(1) = '.'

SELECT CASE WHEN @1 LIKE '%' + @2 + '%'
            THEN REPLACE(@1, @2, '')
            ELSE CONCAT (@1, @2) END

Answer 28

TSQL(Sqlserver 2012), 49 bytes

DECLARE @ VARCHAR(10) = 'hello',@x VARCHAR(10) = 'o'

PRINT IIF(@ LIKE'%'+@x+'%',REPLACE(@,@x,''),@+@x)

Try it online!

Answer 29

k (23 bytes)

{$[#x ss y;,/y\:x;x,y]}

Examples:

k){$[#x ss y;,/y\:x;x,y]}["aba";"a"]
,"b"
k){$[#x ss y;,/y\:x;x,y]}["this string has 6 words ";"now"]
"this string has 6 words now"
k){$[#x ss y;,/y\:x;x,y]}["this string has 5 words now";"now"]
"this string has 5 words "
k){$[#x ss y;,/y\:x;x,y]}["ababa";"ba"]
,"a"
k){$[#x ss y;,/y\:x;x,y]}["";"a"]
,"a"

Answer 30

Kotlin, 61 Bytes

{m:String,t:String->var n=m.replace(t,"");if(m==n)m+t else n}

This is would be shorter if assignment was an expression in Kotlin,and parameters were mutable,and there was a ternary conditional operator, sadly this isn't the case :(

Try it Online!

UnGolfed

fun t(m:String, t:String):String{
    var n=m.replace(t, "")
    return if(m==n)m+t else n
}