Adding increasing key to Hash

Question

PHP allows to add values to array like this:

array[]='a' # result: arr[0]='a'
array[]='a' # result: arr[1]='a'
...

How to achieve similar result with Ruby?

UPDATED: forgot to say, that I need to make some extra hashes inside, like

'a'=>{1=>1}...

UPDATE 2: First update can be a little bit confusing, so there is my full source, which doesn't work. It has to make multiple records of @value hash in session[:items][0], session[:items][1]...

@value = {'id'=>id, 'quantity'=>1, "property_categories"=>params[:property_categories]}

if !session[:items].present?
  session[:items] = @value
else 
  session[:items].push(@value)
end

UPDATE 3: data should look like:

[0=>{'id'=>id, 'quantity'=>1, "property_categories"=>{1=>1}},
1=>{'id'=>id, 'quantity'=>1, "property_categories"=>{1=>1}}]...

Answer 1

In your code, if session[:items] is not present, you are assigning @value(which is a Hash) to it. So next time it will try to push items to Hash.

If you need an Array for session[:items], this should work

if !session[:items].present?
  session[:items] = [@value] # Here create an array with @value in it
else 
  session[:items].push(@value)
end

EDIT I see you have updated your question. So here is my updated answer

if !session[:items].present?
  session[:items] = { 0 => @value }
else
  session[:items][ session[:items].keys.max + 1 ] = @value
end

Answer 2

this should work:

arr << 'a'

or this:

arr.push('a')

source: http://www.ruby-doc.org/core-2.1.1/Array.html

Answer 3

Simply push to the array using <<

array = []
array << 'a' # array == ["a"]
array << 'a' # array == ["a", "a"]