# The beauty of Ruby through examples

**URL:** <https://www.ruby-forum.com/t/the-beauty-of-ruby-through-examples/195768>\
**Category:** Ruby\
**Created:** [September 29, 2010, 8:41pm UTC](https://www.ruby-forum.com/t/the-beauty-of-ruby-through-examples/195768 "2010-09-29T20:41:21Z")\
**Posts on this page:** 20\
**Page:** 1

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**Author:** ![Adriano\_F](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/d6d6ee/32.png) [@Adriano\_F](https://www.ruby-forum.com/u/Adriano_F)\
**Post date:** [September 29, 2010, 8:41pm UTC](https://www.ruby-forum.com/t/the-beauty-of-ruby-through-examples/195768/1 "2010-09-29T20:41:21Z")

</div>

Hey all,

I’m about to introduce Ruby to a group of people that is not familiar to  
the  
language, and the approach i’d like to take is simply by distilling out  
a few  
sample codes. I’ve been collecting some from around the internet, but  
i’d  
appreciate your suggestions as well.

I’m looking for code snippets that represent some of the beauty of Ruby  
actually, such as:

# Simplicity

# Expressiveness

# Productivity

# Flexibility

# Dynamism

# Freedom

# Happiness

Just to clear things up, here are few examples:

# Simplicity

vowels = %w(a e i o u)  
alfabet = (‘a’…‘z’).to\_a  
cons = alfabet - vowels  
p cons

# Expressiveness

hello = ‘Hello Ruby’  
5.times { puts hello }

# Productivity

class Person

# def name

# @name

# end

# 

# def name=(other)

# @name = other

# end

# 

# def age

# @age

# end

# 

# def age=(other)

# @age = other

# end

attr\_accessor :name, :age  
end

john = Person.new  
john.name = ‘John’  
john.age = 25  
p john

# Flexibility

class Array  
def pick  
self[rand(self.size)]  
end

alias :choose :pick  
end

puts %w(1 2 3 4 5).pick  
puts %w(1 2 3 4 5).choose

# Dynamism

Padawan = Class.new

class Jedi  
def train(padawan)  
def padawan.control\_the\_force  
puts “Now i’m ready to become a Jedi!”  
end  
end  
end

skywalker = Padawan.new  
yoda = Jedi.new  
p skywalker.respond\_to? :control\_the\_force # =\> false

yoda.train skywalker  
p skywalker.respond\_to? :control\_the\_force # =\> true  
skywalker.control\_the\_force# =\> Now i’m ready to become a Jedi!

…and so on.

Any more examples?

Thanks in advance,

Adriano

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**Author:** ![Adriano\_F](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/d6d6ee/32.png) [@Adriano\_F](https://www.ruby-forum.com/u/Adriano_F)\
**Post date:** [September 29, 2010, 8:53pm UTC](https://www.ruby-forum.com/t/the-beauty-of-ruby-through-examples/195768/2 "2010-09-29T20:53:03Z")

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I take it rand() gets pseudorandom numbers from computer and as such  
could be improved in one respect at least if ruby can be made to sleep  
or wait for random numbers of milliseconds. One complication with  
random number generation is that two numbers can come off the belt in  
the same millisecond. However making ruby wait a random number of  
milliseconds between each sample draw sample draw is the random numbers  
to provide the user would solve that problem. I just found the Pickaxe  
book the other day and am reading through it and learning. The thing I  
don’t know is how much solving this problem with pseudorandom numbers  
would improve quality of samples.

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**Author:** ![Adriano\_F](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/d6d6ee/32.png) [@Adriano\_F](https://www.ruby-forum.com/u/Adriano_F)\
**Post date:** [September 29, 2010, 9:06pm UTC](https://www.ruby-forum.com/t/the-beauty-of-ruby-through-examples/195768/3 "2010-09-29T21:06:33Z")

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Adriano F. wrote:

> Any more examples?

For wow factor, I think you can’t beat a 4-line webserver written in  
Sinatra.

require ‘sinatra’  
get ‘/’ do  
‘Hello, world!’  
end

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**Author:** ![Adriano\_F](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/d6d6ee/32.png) [@Adriano\_F](https://www.ruby-forum.com/u/Adriano_F)\
**Post date:** [September 29, 2010, 9:30pm UTC](https://www.ruby-forum.com/t/the-beauty-of-ruby-through-examples/195768/4 "2010-09-29T21:30:31Z")

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On Sep 29, 2010, at 9:07 PM, Brian C. wrote:

> For wow factor, I think you can’t beat a 4-line webserver written in  
> Sinatra.

What about a one-line HTTP server written in Lua? 😛

HTTP[‘/’] = function() return ‘Hello world’ end TCPServer(  
‘127.0.0.1’, 1080 )( HTTP )

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**Author:** ![Adriano\_F](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/d6d6ee/32.png) [@Adriano\_F](https://www.ruby-forum.com/u/Adriano_F)\
**Post date:** [September 29, 2010, 9:51pm UTC](https://www.ruby-forum.com/t/the-beauty-of-ruby-through-examples/195768/5 "2010-09-29T21:51:36Z")

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F. Senault wrote:

> end  
> It’s worth mentioning this, too:

puts `grep -i ruby script.rb`

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**Author:** ![Adriano\_F](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/d6d6ee/32.png) [@Adriano\_F](https://www.ruby-forum.com/u/Adriano_F)\
**Post date:** [September 29, 2010, 10:10pm UTC](https://www.ruby-forum.com/t/the-beauty-of-ruby-through-examples/195768/6 "2010-09-29T22:10:35Z")

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I guess you should show irb explicitly.

Another thing worth pointing out: the Ruby source tarball is about 1/3  
of the size of Perl, but you get a whole load more libraries by default:  
openssl, https, md5/sha1 digests, readline, tk, dbm, …

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**Author:** ![Adriano\_F](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/d6d6ee/32.png) [@Adriano\_F](https://www.ruby-forum.com/u/Adriano_F)\
**Post date:** [September 30, 2010, 5:45am UTC](https://www.ruby-forum.com/t/the-beauty-of-ruby-through-examples/195768/7 "2010-09-30T05:45:47Z")

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On Thu, Sep 30, 2010 at 3:30 AM, Petite A.  
[removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote:

> What about a one-line HTTP server written in Lua? 😛
> 
> HTTP[‘/’] = function() return ‘Hello world’ end TCPServer( ‘127.0.0.1’, 1080 )( HTTP )

yes, it’s a one-liner, but, you’ll have to _read_ it many times…  
cheers -botp

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**Author:** ![Adriano\_F](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/d6d6ee/32.png) [@Adriano\_F](https://www.ruby-forum.com/u/Adriano_F)\
**Post date:** [September 29, 2010, 9:31pm UTC](https://www.ruby-forum.com/t/the-beauty-of-ruby-through-examples/195768/8 "2010-09-29T21:31:41Z")

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Le 29 septembre 2010 à 20:40, Adriano F. a écrit :

Hi.

> I’m about to introduce Ruby to a group of people that is not familiar to the  
> language, and the approach i’d like to take is simply by distilling out a few  
> sample codes. I’ve been collecting some from around the internet, but i’d  
> appreciate your suggestions as well.

In a presentation I made sometime ago, I used these at the beginning :

File.open(“script.rb”) do |fichier|  
fichier.each do |ligne|  
if ligne.downcase.include? “ruby”  
puts ligne  
end  
end  
end

File.open(“script.rb”) do |f|  
f.each { |l| puts l if l=~/ruby/i }  
end

# The Lottery here is 7 out of 36 balls.

(1…36).sort\_by { rand }.slice(0,7).join(', ')

fct1 = lambda { |v| v.split(/ /).  
collect { |z| z.capitalize }.join(’ ‘) }  
fct2 = lambda { |v| v.split(//).  
collect { |c| c.ord }.join(’,') }

fct1.call(“this is a nice string.”)  
fct2.call(“this is another nice string.”)

require “open-uri”  
open(‘[http://www.google.com/](http://www.google.com/)’) { |f| puts f.read }

HTH,

Fred

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**Author:** ![Adriano\_F](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/d6d6ee/32.png) [@Adriano\_F](https://www.ruby-forum.com/u/Adriano_F)\
**Post date:** [September 30, 2010, 9:25am UTC](https://www.ruby-forum.com/t/the-beauty-of-ruby-through-examples/195768/9 "2010-09-30T09:25:50Z")

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Le 29 septembre à 21:50, Joel VanderWerf a écrit :

> > f.each { |l| puts l if l=~/ruby/i }  
> > end
> 
> It’s worth mentioning this, too:
> 
> puts `grep -i ruby script.rb`

Yep, nice addition !

Fred

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**Author:** ![Adriano\_F](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/d6d6ee/32.png) [@Adriano\_F](https://www.ruby-forum.com/u/Adriano_F)\
**Post date:** [September 30, 2010, 9:40am UTC](https://www.ruby-forum.com/t/the-beauty-of-ruby-through-examples/195768/10 "2010-09-30T09:40:28Z")

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Le 29 septembre à 21:26, F. Senault a écrit :

And I forgot a simple, classic, one :

def factorial(n)  
(1…n).inject(1) { |p, f| p \* f }  
end

def factorial(n)  
(1…n).inject(1, :\*)  
end

(I don’t like much the second one, it’s a bit less legible.)

Fred

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**Author:** ![Adriano\_F](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/d6d6ee/32.png) [@Adriano\_F](https://www.ruby-forum.com/u/Adriano_F)\
**Post date:** [September 30, 2010, 10:29am UTC](https://www.ruby-forum.com/t/the-beauty-of-ruby-through-examples/195768/11 "2010-09-30T10:29:38Z")

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On Thu, Sep 30, 2010 at 9:35 AM, F. Senault [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote:

> end
> 
> (I don’t like much the second one, it’s a bit less legible.)  
> You see, that depends, it is more readanble to me. Probably totally  
> depends on the context.  
> For folks coming from functional languages the simple fact of using  
> inject’s synonym might also add to readability

(1…n).reduce 1, :\*

In conclusion I prefer naming things, but the downside is that one has  
to communicate names and agree about them. The explicit code block  
does not have that disadvantage. However it does not trigger the  
information in the brain as quickly as names do, once they are  
understood.  
This might indeed be one of the forces and beauties of Ruby and it  
might be a good idea for OP to show that to his audience.

Cheers  
Robert

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**Author:** ![Adriano\_F](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/d6d6ee/32.png) [@Adriano\_F](https://www.ruby-forum.com/u/Adriano_F)\
**Post date:** [September 30, 2010, 10:33am UTC](https://www.ruby-forum.com/t/the-beauty-of-ruby-through-examples/195768/12 "2010-09-30T10:33:09Z")

</div>

On Thu, Sep 30, 2010 at 3:35 PM, F. Senault [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote:

> def factorial(n)  
> (1…n).inject(1, :\*)  
> end  
> (I don’t like much the second one, it’s a bit less legible.)

lose the 1.  
on my case, i do like the second very much. more idiomatic. less prone  
to typo. less to think (convention ie).

i am referring of course, not to the factorial, but of the idiom,

enum.inject :operator  
enum.inject factor, :operator

eg,

multiplying

> > (1…5).inject :\*  
> > =\> 120  
> > (2…5).inject :\*  
> > =\> 120  
> > (3…5).inject :\*  
> > =\> 60

adding

> > (4…5).inject( :+ )  
> > =\> 9

multiply w factor

> > (3…5).inject 5, :\*  
> > =\> 300

adding w initial,

> > (4…5).inject( 100, :+ )  
> > =\> 109

powers,

> > (2…3).inject :\*\*  
> > =\> 8

> > (2…4).inject :\*\*  
> > =\> 4096

and more fun using blocks…

best regards -botp

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**Author:** ![Adriano\_F](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/d6d6ee/32.png) [@Adriano\_F](https://www.ruby-forum.com/u/Adriano_F)\
**Post date:** [September 30, 2010, 11:03am UTC](https://www.ruby-forum.com/t/the-beauty-of-ruby-through-examples/195768/13 "2010-09-30T11:03:36Z")

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On 30 September 2010 10:32, botp [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote:

> On Thu, Sep 30, 2010 at 3:35 PM, F. Senault [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote:
> 
> > def factorial(n)  
> > (1…n).inject(1, :\*)  
> > end  
> > (I don’t like much the second one, it’s a bit less legible.)
> 
> lose the 1.
> 
> -botp

Except if you want factorial of 0 to be right.

While showing a cool example, I would go to:

class Integer  
def !  
(1…self).inject 1, :\*  
end  
end

0.! # =\> 1

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**Author:** ![Adriano\_F](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/d6d6ee/32.png) [@Adriano\_F](https://www.ruby-forum.com/u/Adriano_F)\
**Post date:** [September 30, 2010, 12:18pm UTC](https://www.ruby-forum.com/t/the-beauty-of-ruby-through-examples/195768/14 "2010-09-30T12:18:31Z")

</div>

On Thu, Sep 30, 2010 at 4:58 PM, Benoit D. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)  
wrote:

> Except if you want factorial of 0 to be right.

my bad. i must review my math now 🙂  
best regards -botp

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**Author:** ![Adriano\_F](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/d6d6ee/32.png) [@Adriano\_F](https://www.ruby-forum.com/u/Adriano_F)\
**Post date:** [September 30, 2010, 4:48pm UTC](https://www.ruby-forum.com/t/the-beauty-of-ruby-through-examples/195768/15 "2010-09-30T16:48:39Z")

</div>

def printTree(tree,indent)  
if (Array === tree)  
tree.map { |child| printTree(child,indent+"| “) }  
else  
puts(indent.gsub(/\s+$/,”–")+tree.to\_s)  
end  
end  
printTree([1,2,[11,22,[111,222,333,444],33],3,4],"")

this give :  
|–1  
|–2  
| |–11  
| |–22  
| | |–111  
| | |–222  
| | |–333  
| | |–444  
| |–33  
|–3  
|–4

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**Author:** ![Adriano\_F](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/d6d6ee/32.png) [@Adriano\_F](https://www.ruby-forum.com/u/Adriano_F)\
**Post date:** [October 1, 2010, 4:01am UTC](https://www.ruby-forum.com/t/the-beauty-of-ruby-through-examples/195768/16 "2010-10-01T04:01:28Z")

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On 09/30/2010 07:48 AM, Regis d’Aubarede wrote:

> def printTree(tree,indent)  
> if (Array === tree)  
> tree.map { |child| printTree(child,indent+"| “) }  
> else  
> puts(indent.gsub(/\s+$/,”–")+tree.to\_s)  
> end  
> end  
> printTree([1,2,[11,22,[111,222,333,444],33],3,4],"")

IMO this is more idiomatic:

class Object  
def recursive\_print indent = “”  
puts indent.gsub(/\s+$/,"–") + to\_s  
end  
end

module Enumerable  
def recursive\_print indent = “”  
map { |child| child.recursive\_print indent+"| " }  
end  
end

[1,2,[11,22,[111,222,333,444],33],3,4].recursive\_print

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**Author:** ![Adriano\_F](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/d6d6ee/32.png) [@Adriano\_F](https://www.ruby-forum.com/u/Adriano_F)\
**Post date:** [October 1, 2010, 7:14am UTC](https://www.ruby-forum.com/t/the-beauty-of-ruby-through-examples/195768/17 "2010-10-01T07:14:03Z")

</div>

How about some more simple ones like

'Do Re Mi Fa So La Ti ’ \* 3

[125, 450, 250, 1000, 675].sort.reverse.collect{|e| “$#{e}”}.take(3)

’ hello there '.strip.center(30, ‘-’)

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**Author:** ![Adriano\_F](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/d6d6ee/32.png) [@Adriano\_F](https://www.ruby-forum.com/u/Adriano_F)\
**Post date:** [September 30, 2010, 4:35pm UTC](https://www.ruby-forum.com/t/the-beauty-of-ruby-through-examples/195768/18 "2010-09-30T16:35:50Z")

</div>

Threading is light in ruby, so here a try show works in paralleles :

require ‘thread’  
require ‘socket’  
require ‘timeout’

############### Send a file by socket to www server

def send\_file(hostname,filename)  
timeout(3+File.size(filename)/10000) { # timeout, in seconds  
socket=TCPSocket.open(hostname,80)  
socket.write( “POST /upload/#{filename} HTTP/1.1\r\n\r\nContent=” )  
socket.write( IO.read(filename) )  
print “\n#{filename} transfered”  
}  
rescue Exception =\> ex  
puts “ERROR on transfert #{filename} to {hostname} : #{ex}”  
ensure  
socket.close rescue nil # anyway, try to close  
end

################### MAIN : send \*.rb in //

threads= Dir["\*.rb"].map do |file|  
sleep(0.1) while Thread.list.size\>20  
Thread.new { send\_file(ARGV[0],file) }  
end  
threads.each {|thread| thread.join} # wait all finish before exit

---

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**Author:** ![Adriano\_F](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/d6d6ee/32.png) [@Adriano\_F](https://www.ruby-forum.com/u/Adriano_F)\
**Post date:** [October 1, 2010, 8:44am UTC](https://www.ruby-forum.com/t/the-beauty-of-ruby-through-examples/195768/19 "2010-10-01T08:44:06Z")

</div>

> end
> 
> skywalker = Padawan.new  
> yoda = Jedi.new  
> p skywalker.respond\_to? :control\_the\_force # =\> false
> 
> yoda.train skywalker  
> p skywalker.respond\_to? :control\_the\_force # =\> true  
> skywalker.control\_the\_force# =\> Now i’m ready to become a Jedi!

Wow, these are fantastic, especially this last one. I don’t know if  
this syntax (def padawan.control\_the\_force) has always been available  
but I have long been doing that in a much more complicated way.

Please post your full list or your slides when you are finished! So  
often people ask me “what’s so great about Ruby” and I can’t put it  
into just a few sentences!

---

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**Author:** ![Adriano\_F](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/d6d6ee/32.png) [@Adriano\_F](https://www.ruby-forum.com/u/Adriano_F)\
**Post date:** [October 2, 2010, 4:25pm UTC](https://www.ruby-forum.com/t/the-beauty-of-ruby-through-examples/195768/20 "2010-10-02T16:25:40Z")

</div>

On Sep 29, 1:40 pm, Adriano F. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote:

> actually, such as:
> 
> 5.times { puts hello }
> 
> # end
> 
> end  
> self[rand(self.size)]  
> Padawan = Class.new  
> yoda = Jedi.new  
> Thanks in advance,
> 
> Adriano

In comp.lang.lisp, this elisp code was posted as an example  
of how to shuffle a vector:

(defun emms-shuffle-vector (vector)  
“Shuffle VECTOR.”  
(let ((i (- (length vector) 1)))  
(while (\>= i 0)  
(let\* ((r (random (1+ i)))  
(old (aref vector r)))  
(aset vector r (aref vector i))  
(aset vector i old))  
(setq i (- i 1))))  
vector)

Ruby:

(9…20).sort\_by{ rand }  
==\>[15, 14, 12, 18, 16, 10, 9, 13, 11, 20, 17, 19]

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