Boo! A Halloween Code Golf Challenge

Question

Write a program that takes an input string of length 2 or more characters and adds the string ~BOO!~ (that string has a leading and ending space) in a uniformly random spot in the string that is not on either end.

---

Disallowed sample inputs: 2 or (an empty input)

Disallowed sample outputs: Hello ~BOO!~ or ~BOO!~ Hello for the input Hello

Sample input: Hello, World!

Sample outputs: Hel ~BOO!~ lo, World! or Hello, Worl ~BOO!~ d!

---

This is code golf, fellas. Standard rules apply. Shortest code in bytes wins.

---

Congratulations to Dennis for having the shortest, spookiest program! Happy Halloween!

Answer 1

Pyth, 19 18 bytes

j" ~BOO!~ "cz]OtUz

Thanks to @Jakube for golfing off 1 byte!

Try it online.

How it works

                    (implicit) Store the input in z.
                Uz  Compute [0, ... len(z)-1].
               t    Remove the first element.
              O     Select an integer, pseudo-randomly.
             ]      Wrap it in an array.
           cz       Split the input string at that point.
j" ~BOO!~ "         Join the split string, using " ~BOO!~ " as separator.

Answer 2

GML, 91 bytes

s=get_string("","")
show_message(string_insert(" ~BOO!~ ",s,irandom(string_length(s)-2)+1);

Simple enough - get a string, insert the substring into it, output the string. Done.

Answer 3

Python 3, 60 bytes

s=input();n=1+hash(s)%(len(s)-1);print(s[:n],'~BOO!~',s[n:])

Note:

The modulo of hash() will be uniformly distributed over the length of the string. If you think that's bending the rules, note that because of python's hash randomization, this is actually random: repeated executions with the same input will give different results.

Answer 4

CJam, 20 bytes

l_,(mr)/(" ~BOO!~ "@

Try it online

Explanation:

l       Get input.
_,      Calculate length.
(       Decrement, since the number of possible positions is 1 less than length.
mr      Generate random number between 0 and length-2
)       Increment, giving random number between 1 and length-1.
/       Split. Note that this splits repeatedly, but this will not do any harm.
        We will only really use the first split.
(       Peel off the first fragment after the split.
" ~BOO!~ "
        Push the magic string.
@       Rotate the list with the remaining fragments to the top.

Answer 5

Pip, 19 bytes

Takes input from the command-line. If the input has spaces or other special characters, it will need to be placed in quotes.

a^@1RR#aJ" ~BOO!~ "

Explanation:

a                    Command-line arg
 ^@                  Split at index...
   1RR#a             ...random integer >= 1 and < length(a) (Python randrange)
        J" ~BOO!~ "  Join on that string and autoprint

Answer 6

Julia, 70 bytes

print((s=readline())[1:(r=rand(2:length(s)-2))]," ~BOO!~ ",s[r+1:end])

Ungolfed:

# Read a line from STDIN
s = readline()

# Define a random integer within the bounds of s
r = rand(2:length(s)-2)

# Print to STDOUT with boo in there somewhere
print(s[1:r], " ~BOO!~ ", s[r+1:end])

Answer 7

APL, 27 bytes

{(-⌽' ~BOO!~ ',⍵⌽⍨⊢)?¯1+⍴⍵}

APL doesn't have an insert function, so we rotate the string instead.

{                          }    ⍝ Monadic function:
                     ?¯1+⍴⍵     ⍝ Place to insert string, let's say it's X
 (                  )           ⍝ Monadic train:
               ⍵⌽⍨⊢            ⍝ Rotate input by X (⊢) to the left
    ' ~BOO!~ ',                 ⍝ Concatenate ' ~BOO!~ '
  -                             ⍝ -X
   ⌽                            ⍝ Rotate that by X to the right

Example input on TryAPL

Answer 8

Lua, 75 bytes

s=io.read()m=math.random(2,#s/2);return s:sub(1,m).." ~BOO!~ "..s:sub(m,#s)

Answer 9

Python 3, 79 bytes

from random import*;s=input();n=randint(1,len(s)-1);print(s[:n],'~BOO!~',s[n:])

Try it online

Pretty self-explanatory - read a string, pick a random integer between 1 and the length of the string, and print the string with ' ~BOO!~ ' inserted.

Answer 10

Perl, 35 bytes

34 bytes code + 1 byte command line

$-=rand y///c-2;s/..{$-}\K/~BOO!~/

Usage:

perl -p entry.pl

Answer 11

C#, 125 bytes

using System;class X{static void Main(string[]a){Console.Write(a[0].Insert(new Random().Next(a[0].Length-2)+1," ~BOO!~ "));}}

Expanded:

using System;
class X
{
    static void Main(string[] a)
    {
        Console.Write(a[0].Insert(new Random().Next(a[0].Length - 2) + 1, " ~BOO!~ "));
    }
}

This solution assumes that the string is passed in as the first command-line parameter. This is not usual for C# (stdin is more normal), so I’ve also included a solution that uses normal stdin:

C#, 139 bytes

using System;class X{static void Main(){var x=Console.In.ReadToEnd();Console.Write(x.Insert(new Random().Next(x.Length-2)+1," ~BOO!~ "));}}

Expanded:

using System;
class X
{
    static void Main()
    {
        var x = Console.In.ReadToEnd();
        Console.Write(x.Insert(new Random().Next(x.Length - 2) + 1, " ~BOO!~ "));
    }
}

Answer 12

MATLAB, 69 bytes

i=input('');a=randi(nnz(i)-1,1);disp([i(1:a) ' ~Boo!~ ' i(a+1:end)]);

Inserting a string mid string at a given index in MATLAB is costly in terms of bytes. If there was a simple way to do it, I could save a fair amount by moving to an anonymous function, but I can't find one. Ah well.

Basically it gets a random number between 1 and the length of the string minus 1. Then it displays everything up to and including that index, followed by the ~Boo!~, and then everything after the index to the end.

---

It also works with Octave, so you can try it out online here.

Answer 13

Vitsy, 19 Bytes

Note that z and Z were edited today, but not for this challenge.

I1-R1+\i" ~OOB~ "zZ
I1-                   Get the length of the input, minus 1
   R                  Push a random number from 0 to the top item of the stack.
    1+                Add one to it - this is now a random number from 1 to input
                      length - 1.
      \i              Get that many items of input.
        " ~OOB~ "     Push ' ~BOO~ ' to the stack.
                 z    Get the rest of the input.
                  Z   Output it all.

Answer 14

Bash/GNU, 61 bytes

echo $1|sed "s/.\{`shuf -i1-$((${#1}-1)) -n1`\}/\0 ~BOO!~ /"

Takes input string as argument

Answer 15

Ruby, 46 bytes

$><<gets.insert(rand(1..$_.size-2),' ~BOO!~ ')

Answer 16

JavaScript, 79

r=Math.random()*((x=prompt()).length-1)+1;x.substr(0,r)+" ~BOO!~ "+x.substr(r);

It's for the browser console; have fun just popping that in.

Answer 17

Java 8, 158 154 bytes

interface M{static void main(String[]a){int i=a[0].length()-2;System.out.println(a[0].substring(0,i=1+(i*=Math.random()))+" ~BOO!~ "+a[0].substring(i));}}

Try it here.

EDIT: Only now reading program instead of the default function/program in the challenge description.. So added the bordercode with interface and main method.

If a function would be allowed it would be (99 95 bytes)

s->{int i=s.length()-2;return s.substring(0,i=1+(i*=Math.random()))+" ~BOO!~ "+s.substring(i);}

Try it here.

Explanation:

s->{                        // Method with String as both parameter and return-type
  int i=s.length()-2;       //  The length of the input - 2
  return s.substring(0,i=1  //  Return the first part of the input from index 0 to 1
    +(i*=Math.random()))    //    + a random integer between 0 and length-2
   +" ~BOO!~ "              //   appended with the literal " ~BOO!~ "
   +s.substring(i);         //   appended with the rest of the input-String
}                           // End of method

Answer 18

Chaîne, 23 bytes

{il1-R1+`} ~BOO!~ {<$/}

Answer 19

TeaScript, 30 bytes

xh(j=N(xn-1)+1)+' ~BOO!~ '+xS(j)

Very straight forward.

Answer 20

CJam, 19 bytes

q_,mr)/(" ~BOO!~ "@