Help solving a problem

rubyonrails-talk
1

Hello all,

I am reading the book Ruby on Rails Tutorial : Learning by Example

At the end of chapter 4 theres a question. I tried many time but nit succeeding in solving it.

Can you all please help me in writing a solution for the same?

Question is :

Using Listing 4.9 as a guide, combine the split, shuffle, and join methods to write a function that shuffles the letters in a given string.

Listing 4.9. Skeleton for a string shuffle function :

def string_shuffle(s)   s.split('').?.? end

=> nil

string_shuffle("foobar")

Thank you

2

Hi, to tackle such a question, I would use a combination of:

the result of each intermediate step is

So, in the session below, you see how I would build-up the result of your

excersize:

peterv@ASUS:~$ ruby -v

ruby 1.9.3p0 (2011-10-30 revision 33570) [i686-linux]

peterv@ASUS:~$ irb

001:0> s = “foobar”

=> “foobar”

002:0> s.class

=> String

003:0> s.inspect

=> “"foobar"”

004:0> # now look up the documentation for String#split (http://www.ruby-doc.org/core-1.9.3/String.html)

005:0* ^C

005:0> s_split = s.split(‘’)

=> [“f”, “o”, “o”, “b”, “a”, “r”]

006:0> # now look up the documentation for Array#shuffle

007:0* ^C

007:0> s_split_shuffle = s_split.shuffle

=> [“o”, “o”, “f”, “r”, “a”, “b”]

008:0> s_split_shuffle.class

=> Array

009:0> # now look up the documentation for Array#join

010:0* ^C

010:0> result = s_split_shuffle.join

=> “oofrab”

011:0> result.class

=> String

012:0> # so the answer is s.split(‘’).shuffle.join

013:0* ^C

HTH,

Peter

3

Hi, to tackle such a question, I would use a combination of:

* irb (or pry) * ruby documentation (e.g. class Array - RDoc Documentation) * use the .class and .inspect method intensively to study what type and content   the result of each intermediate step is

So, in the session below, you see how I would build-up the result of your excersize:

peterv@ASUS:~$ ruby -v ruby 1.9.3p0 (2011-10-30 revision 33570) [i686-linux] peterv@ASUS:~$ irb 001:0> s = "foobar" => "foobar" 002:0> s.class => String 003:0> s.inspect => "\"foobar\"" 004:0> # now look up the documentation for String#split ( Class: String (Ruby 1.9.3)) 005:0* ^C 005:0> s_split = s.split('') => ["f", "o", "o", "b", "a", "r"] 006:0> # now look up the documentation for Array#shuffle 007:0* ^C 007:0> s_split_shuffle = s_split.shuffle => ["o", "o", "f", "r", "a", "b"] 008:0> s_split_shuffle.class => Array 009:0> # now look up the documentation for Array#join 010:0* ^C 010:0> result = s_split_shuffle.join => "oofrab" 011:0> result.c

Thanks a lot mate. I was doing maximum right, but the way I was usaging the split and shuffle was wrong.