In php i can do this:
$access = array();
$access['drivers']['create'] = 'administrator';
$access['drivers']['view'] = 'user';
echo $access['drivers']['view']; # => 'user'
How can i do it in Ruby?
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is it necessary to imperatively modify "access" or it can be defined in one step?tokland– tokland2011-06-24 16:13:55 +00:00Commented Jun 24, 2011 at 16:13
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Out of curiosity, what resources have you been using to learn Ruby (apart from Stack Overflow)?Andrew Grimm– Andrew Grimm2011-06-25 00:45:53 +00:00Commented Jun 25, 2011 at 0:45
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1To learn Ruby i am doing web-project on ROR. Some answers i got from Programming Ruby 1.9 book, some in google and some here.Vladimir Tsukanov– Vladimir Tsukanov2011-06-25 10:52:41 +00:00Commented Jun 25, 2011 at 10:52
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5 Answers
With a hash.
access = Hash.new # or {}
access["drivers"] = {}
access["drivers"]["view"] = 'user'
You can use an array as the key if you want.
access = Hash.new
access["drivers", "view"] = "user"
Comments
You mean something like this?
#!/usr/bin/env ruby
access = Hash.new
access['drivers'] = Hash.new
access['drivers']['create'] = 'administrator'
access['drivers']['view'] = 'user'
puts access['drivers']['view'] # => 'user'
Comments
It's Worth Noting that the convention is often to use :symbols instead of "strings"
access[:drivers][:view]
they are basically just immutable strings. Since strings are mutable objects in Ruby, hashes convert them to immutable ones internally ( to a symbol no less ) but you can do it explicitly and it looks a little cleaner in my opinion.
Comments
You could use the block form of Hash.new to provide an empty Hash as a default value:
h = Hash.new { |h,k| h[k] = { }; h[k].default_proc = h.default_proc; h[k] }
And then this happens:
>> h[:this][:that] = 6
# h = {:this=>{:that=>6}}
>> h[:other][:that] = 6
# {:this=>{:that=>6}, :other=>{:that=>6}}
>> h[:thing][:that] = 83724
# {:this=>{:that=>6}, :other=>{:that=>6}, :thing=>{:that=>83724}}
The funny looking default_proc stuff in the block shares the main hash's default value generating block with the sub-hashes so that they auto-vivify too.
Also, make sure you don't do this:
h = Hash.new({ })
to supply a hash as a default value, there is some explanation of why not over in this answer.
Comments
From the question is unclear if you really need to update the structure. I'd most write something like this:
access = {
:drivers => {
:create => "administrator",
:view => "user",
},
}
access[:drivers][:view] #=> 'user'
