Something like that:
arr=[]
arr[some variable] << string
How to accomplish that on Ruby?
Thanks ;)
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1What are you trying to accomplish, i.e., what should arr be after this? I can't tell if you're just trying to set a hash value (e.g., h={}; h[key]=value) or do something else.Bill Dueber– Bill Dueber2011-05-30 15:20:33 +00:00Commented May 30, 2011 at 15:20
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4 Answers
In Ruby a Hash can be treated as an associative array.
# Initialize the hash.
noises = {}
# => {}
# Add items to the hash.
noises[:cow] = 'moo'
# => { :cow => 'moo' }
# Dynamically add items.
animal = 'duck'
noise = 'quack'
noises[animal] = noise
# => { :cow => 'moo', 'duck' => 'quack' }
As you can see anything can be a key, in this example I have used both a symbol, :cow and a String, 'duck'.
The Ruby Hash documentation contains all the examples you could ever need.
2 Comments
Somebody
Thanks mate i have already found that out :D. Btw what differens in [:cow] and ['cow'] ?
Douglas F Shearer
They're just different classes used as keys. You can have both in the same hash
{ :cow => 'moo', 'cow' => 'moo' }Hash is what you need. And you can take advantage of the default value creation when the key does not exist. That's in your case an empty array. Here is the snippet:
# this creates you a hash with a default value of an empty array
your_hash = Hash.new { |hash, key| hash[key] = Array.new }
your_hash["x"] << "foo"
your_hash["x"] << "za"
your_hash["y"] << "bar"
your_hash["x"] # ==> ["foo", "za"]
your_hash["y"] # ==> ["bar"]
your_hash["z"] # ==> []
Check out the ruby documentation of the Hash class: http://ruby-doc.org/core/classes/Hash.html.
Comments
You can simply do this
arr={}
arr["key"] = "string"
or
arr[:key] = "string"
and access it like
arr["key"]
arr[:key]
Comments
You should use Hash instead of Array in Ruby. Arrays in Ruby are not associative.
>> h = {'a' => [1, 2]}
>> key = 'a'
>> value = 3
>> h[key] << value
>> puts h
=> {"a"=>[1, 2, 3]}
3 Comments
tokland
what happened to the old h[key] = value?
Somebody
More elegant solution? Doesn't Ruby have the most beautiful and elegant syntax? :D
Douglas F Shearer
Why do the examples call
send?