New to Ruby - how do I shuffle a string?

Question

Want to shuffle a string. This is my code: what is wrong about it? Thanks.

>> def string_shuffle(s)
>>   s.split('').shuffle(s.length()).join
>>   return s
>> end

score 24 · Accepted Answer · answered Aug 10 '11 at 08:06

24

If understand you correctly, you want this:

def string_shuffle(s)
  s.split("").shuffle.join
end

string_shuffle("The Ruby language")
=> "ea gu bgTayehRlnu"

answered Aug 10 '11 at 08:06

kyrylo

1,691
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1

If you need a lot of shuffling it makes sense to use `shuffle!` instead of `shuffle`. It is a bit faster. – defhlt Dec 03 '12 at 20:31
4

You can use `chars` instead of `split("")` – Nic Sep 08 '16 at 17:07

score 8 · Answer 2 · answered Aug 10 '11 at 08:09

8

return s is both not needed and wrong. Not needed because Ruby returns whatever is executed last and wrong because you are not changing s, you are creating a new string.

Furthermore, you can just add the shuffle method directly to String if you find it useful, but beware of monkeypatching too much.

class String

  def shuffle
    self.split('').shuffle.join
  end
end

answered Aug 10 '11 at 08:09

Serabe

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you could put this in a module then apply the module to the string you want to affect, that ways it wont affect other strings in the app and cause unwanted effects. – Joseph Le Brech Aug 10 '11 at 08:13
@Joseph, how do you get a module to affect a specific string instance? An example or link would be great. Also, Josh, you may find this [question about monkeypatching](http://stackoverflow.com/questions/394144/what-does-monkey-patching-exactly-mean-in-ruby) useful. – Zabba Aug 10 '11 at 08:17
@Zabba http://www.ruby-doc.org/core/classes/Module.html check extend. it monkey patches a variable rather than a class. – Joseph Le Brech Aug 10 '11 at 08:46
Besides, explore the differences between including a module and extending it. One common pattern is using the self.included method in the module for extending another one, so it _includes_ a few class methods. – Serabe Aug 10 '11 at 09:07

score 7 · Answer 3 · answered Sep 23 '15 at 23:14

This is faster. 'hello'.chars.shuffle.join

Test yourself:

require 'benchmark'

str = 'Hello' * 100
Benchmark.bm(10) do |x|
  x.report('chars')       { str.chars.shuffle.join }
  x.report('split')       { str.split('').shuffle.join }
  x.report('split regex') { str.split(//).shuffle.join }
end

score 2 · Answer 4 · answered Aug 10 '11 at 08:06

2

shuffle does not accept (and need) arguments. Use:

 s.split(//).shuffle.to_s

answered Aug 10 '11 at 08:06

Emiliano Poggi

24,390
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score 1 · Answer 5 · answered Mar 01 '18 at 16:24

1

This will do:

s.chars.shuffle.join

Example:

s = "Hello, World!"
puts s.chars.shuffle.join

Output:

olH!l rWdel,o

answered Mar 01 '18 at 16:24

kwyntes

1,045
10
27

score 1 · Answer 6 · answered Aug 10 '11 at 08:39

1

try this

s.split('').shuffle.join

answered Aug 10 '11 at 08:39

Dnyan Waychal

1,418
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New to Ruby - how do I shuffle a string?

6 Answers6